<?xml version="1.0" encoding="us-ascii"?><InstanceReport xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><Version>2.4.0.8</Version><ReportLongName>0017 - Disclosure - Change in Fair Value of Warrant Liability</ReportLongName><DisplayLabelColumn>true</DisplayLabelColumn><ShowElementNames>false</ShowElementNames><RoundingOption /><HasEmbeddedReports>false</HasEmbeddedReports><Columns><Column FlagID="0"><Id>1</Id><IsAbstractGroupTitle>false</IsAbstractGroupTitle><LabelSeparator>

</LabelSeparator><CurrencyCode /><FootnoteIndexer /><hasSegments>false</hasSegments><hasScenarios>false</hasScenarios><MCU><KeyName /><CurrencySymbol /><contextRef><ContextID>From2013-01-01to2013-06-30</ContextID><EntitySchema>http://www.sec.gov/CIK</EntitySchema><EntityValue>0001125699</EntityValue><PeriodDisplayName /><PeriodType>duration</PeriodType><PeriodStartDate>2013-01-01T00:00:00</PeriodStartDate><PeriodEndDate>2013-06-30T00:00:00</PeriodEndDate><Segments /><Scenarios /></contextRef><UPS /><CurrencyCode /><OriginalCurrencyCode /></MCU><CurrencySymbol /><Labels><Label Key="CalendarSupplement" Id="0" Label="6 Months Ended" /><Label Key="Calendar" Id="1" Label="Jun. 30, 2013" /></Labels></Column></Columns><Rows><Row FlagID="0"><Id>1</Id><IsAbstractGroupTitle>true</IsAbstractGroupTitle><LabelSeparator>

</LabelSeparator><Level>1</Level><ElementName>DLYT_NotesToFinancialStatementsAbstract</ElementName><ElementPrefix>DLYT_</ElementPrefix><IsBaseElement>false</IsBaseElement><BalanceType>na</BalanceType><PeriodType>duration</PeriodType><IsReportTitle>false</IsReportTitle><IsSegmentTitle>false</IsSegmentTitle><IsCalendarTitle>false</IsCalendarTitle><IsEquityPrevioslyReportedAsRow>false</IsEquityPrevioslyReportedAsRow><IsEquityAdjustmentRow>false</IsEquityAdjustmentRow><IsBeginningBalance>false</IsBeginningBalance><IsEndingBalance>false</IsEndingBalance><IsReverseSign>false</IsReverseSign><FootnoteIndexer /><Cells><Cell FlagID="0" ContextID="" UnitID=""><Id>1</Id><IsNumeric>false</IsNumeric><IsRatio>false</IsRatio><DisplayZeroAsNone>false</DisplayZeroAsNone><NumericAmount>0</NumericAmount><RoundedNumericAmount>0</RoundedNumericAmount><NonNumbericText /><FootnoteIndexer /><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat></Cell></Cells><ElementDataType>xbrli:stringItemType</ElementDataType><SimpleDataType>string</SimpleDataType><IsTotalLabel>false</IsTotalLabel><UnitID>0</UnitID><Label>Notes to Financial Statements</Label></Row><Row FlagID="0"><Id>2</Id><IsAbstractGroupTitle>false</IsAbstractGroupTitle><LabelSeparator>

</LabelSeparator><Level>2</Level><ElementName>DLYT_ChangeInFairValueOfWarrantLiabilityTextBlock</ElementName><ElementPrefix>DLYT_</ElementPrefix><IsBaseElement>false</IsBaseElement><BalanceType>na</BalanceType><PeriodType>duration</PeriodType><IsReportTitle>false</IsReportTitle><IsSegmentTitle>false</IsSegmentTitle><IsCalendarTitle>false</IsCalendarTitle><IsEquityPrevioslyReportedAsRow>false</IsEquityPrevioslyReportedAsRow><IsEquityAdjustmentRow>false</IsEquityAdjustmentRow><IsBeginningBalance>false</IsBeginningBalance><IsEndingBalance>false</IsEndingBalance><IsReverseSign>false</IsReverseSign><FootnoteIndexer /><Cells><Cell FlagID="0" ContextID="From2013-01-01to2013-06-30" UnitID=""><Id>1</Id><IsNumeric>false</IsNumeric><IsRatio>false</IsRatio><DisplayZeroAsNone>false</DisplayZeroAsNone><NumericAmount>0</NumericAmount><RoundedNumericAmount>0</RoundedNumericAmount><NonNumbericText>&lt;p style="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify"&gt;The Company has accounted for certain
warrants in accordance with ASC 815-10, Derivatives and Hedging (ASC 815-10). ASC 815-10 provides guidance for determining
whether an equity-linked financial instrument (or embedded feature) is indexed to an entity&amp;#146;s own stock. This applies to
any freestanding financial instrument or embedded feature that has all the characteristics of a derivative under ASC 815-10,
including any freestanding financial instrument that is potentially settled in an entity&amp;#146;s own stock.&lt;/p&gt;

&lt;p style="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify; text-indent: 0.5in"&gt;&amp;#160;&lt;/p&gt;

&lt;p style="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify"&gt;Due to certain adjustments that may be made
to the exercise price of the warrants issued in December 2007, January 2008 and August 2008 if the Company issues or sells shares
of its common stock at a price which is less than the then current warrant exercise price, these warrants have been classified
as a liability as opposed to equity in accordance with the Derivatives and Hedging Topic of the FASB ASC 815-10-15 as it was determined
that these warrants were not indexed to the Company&amp;#146;s stock&lt;i&gt;.&amp;#160;&lt;/i&gt;As a result, the fair market value of these warrants
was remeasured on January 1, 2009 and marked to market at each subsequent financial reporting period. The change in fair value
of the warrants is recorded in the statement of operations and is estimated using the Black-Scholes option-pricing model with the
following assumptions:&lt;/p&gt;

&lt;p style="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify; text-indent: 0.5in"&gt;&amp;#160;&lt;/p&gt;

&lt;table cellspacing="0" cellpadding="0" style="font: 10pt Times New Roman, Times, Serif; width: 100%"&gt;
&lt;tr style="vertical-align: bottom; background-color: white"&gt;
    &lt;td&gt;&amp;#160;&lt;/td&gt;
    &lt;td&gt;&amp;#160;&lt;/td&gt;
    &lt;td colspan="2" style="border-bottom: black 1.5pt solid"&gt;
        &lt;p style="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: center"&gt;&lt;b&gt;For the Three &lt;/b&gt;&lt;/p&gt;
        &lt;p style="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: center"&gt;&lt;b&gt;Months Ended&lt;/b&gt;&lt;/p&gt;
        &lt;p style="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: center"&gt;&lt;b&gt;June 30, 2012&lt;/b&gt;&lt;/p&gt;&lt;/td&gt;
    &lt;td nowrap="nowrap"&gt;&amp;#160;&lt;/td&gt;
    &lt;td&gt;&amp;#160;&lt;/td&gt;
    &lt;td colspan="2" style="border-bottom: black 1.5pt solid"&gt;
        &lt;p style="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: center"&gt;&lt;b&gt;For the Six&lt;/b&gt;&lt;/p&gt;
        &lt;p style="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: center"&gt;&lt;b&gt;Months Ended&lt;/b&gt;&lt;/p&gt;
        &lt;p style="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: center"&gt;&lt;b&gt;June 30, 2012&lt;/b&gt;&lt;/p&gt;&lt;/td&gt;
    &lt;td nowrap="nowrap"&gt;&amp;#160;&lt;/td&gt;&lt;/tr&gt;
&lt;tr style="vertical-align: bottom; background-color: white"&gt;
    &lt;td&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="text-align: right"&gt;&amp;#160;&lt;/td&gt;
    &lt;td colspan="2" style="text-align: right"&gt;&amp;#160;&lt;/td&gt;
    &lt;td nowrap="nowrap"&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="text-align: right"&gt;&amp;#160;&lt;/td&gt;
    &lt;td colspan="2" style="text-align: right"&gt;&amp;#160;&lt;/td&gt;
    &lt;td nowrap="nowrap"&gt;&amp;#160;&lt;/td&gt;&lt;/tr&gt;
&lt;tr style="vertical-align: bottom; background-color: #CCEEFF"&gt;
    &lt;td style="width: 78%"&gt;&lt;font style="font-size: 10pt"&gt;Exercise price&lt;/font&gt;&lt;/td&gt;
    &lt;td style="width: 1%; text-align: right"&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="width: 1%"&gt;&lt;font style="font-size: 10pt"&gt;$&lt;/font&gt;&lt;/td&gt;
    &lt;td style="width: 8%; text-align: right"&gt;&lt;font style="font-size: 10pt"&gt;0.25&lt;/font&gt;&lt;/td&gt;
    &lt;td nowrap="nowrap" style="width: 1%"&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="width: 1%; text-align: right"&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="width: 1%"&gt;&lt;font style="font-size: 10pt"&gt;$&lt;/font&gt;&lt;/td&gt;
    &lt;td style="width: 8%; text-align: right"&gt;&lt;font style="font-size: 10pt"&gt;0.25&lt;/font&gt;&lt;/td&gt;
    &lt;td nowrap="nowrap" style="width: 1%"&gt;&amp;#160;&lt;/td&gt;&lt;/tr&gt;
&lt;tr style="vertical-align: bottom; background-color: white"&gt;
    &lt;td&gt;&lt;font style="font-size: 10pt"&gt;Market value of stock at end of period&lt;/font&gt;&lt;/td&gt;
    &lt;td style="text-align: right"&gt;&amp;#160;&lt;/td&gt;
    &lt;td&gt;&lt;font style="font-size: 10pt"&gt;$&lt;/font&gt;&lt;/td&gt;
    &lt;td style="text-align: right"&gt;&lt;font style="font-size: 10pt"&gt;0.10&lt;/font&gt;&lt;/td&gt;
    &lt;td nowrap="nowrap"&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="text-align: right"&gt;&amp;#160;&lt;/td&gt;
    &lt;td&gt;&lt;font style="font-size: 10pt"&gt;$&lt;/font&gt;&lt;/td&gt;
    &lt;td style="text-align: right"&gt;&lt;font style="font-size: 10pt"&gt;0.10&lt;/font&gt;&lt;/td&gt;
    &lt;td nowrap="nowrap"&gt;&amp;#160;&lt;/td&gt;&lt;/tr&gt;
&lt;tr style="vertical-align: bottom; background-color: #CCEEFF"&gt;
    &lt;td&gt;&lt;font style="font-size: 10pt"&gt;Expected dividend rate&lt;/font&gt;&lt;/td&gt;
    &lt;td style="text-align: right"&gt;&amp;#160;&lt;/td&gt;
    &lt;td&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="text-align: right"&gt;&lt;font style="font-size: 10pt"&gt;0 &lt;/font&gt;&lt;/td&gt;
    &lt;td nowrap="nowrap"&gt;&lt;font style="font-size: 10pt"&gt;%&lt;/font&gt;&lt;/td&gt;
    &lt;td style="text-align: right"&gt;&amp;#160;&lt;/td&gt;
    &lt;td&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="text-align: right"&gt;&lt;font style="font-size: 10pt"&gt;0 &lt;/font&gt;&lt;/td&gt;
    &lt;td nowrap="nowrap"&gt;&lt;font style="font-size: 10pt"&gt;%&lt;/font&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr style="vertical-align: bottom; background-color: white"&gt;
    &lt;td&gt;&lt;font style="font-size: 10pt"&gt;Expected volatility&lt;/font&gt;&lt;/td&gt;
    &lt;td style="text-align: right"&gt;&amp;#160;&lt;/td&gt;
    &lt;td&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="text-align: right"&gt;&lt;font style="font-size: 10pt"&gt;183% - 191 &lt;/font&gt;&lt;/td&gt;
    &lt;td nowrap="nowrap"&gt;&lt;font style="font-size: 10pt"&gt;%&lt;/font&gt;&lt;/td&gt;
    &lt;td style="text-align: right"&gt;&amp;#160;&lt;/td&gt;
    &lt;td&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="text-align: right"&gt;&lt;font style="font-size: 10pt"&gt;183% - 191 &lt;/font&gt;&lt;/td&gt;
    &lt;td nowrap="nowrap"&gt;&lt;font style="font-size: 10pt"&gt;%&lt;/font&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr style="vertical-align: bottom; background-color: #CCEEFF"&gt;
    &lt;td&gt;&lt;font style="font-size: 10pt"&gt;Risk-free interest rate&lt;/font&gt;&lt;/td&gt;
    &lt;td style="text-align: right"&gt;&amp;#160;&lt;/td&gt;
    &lt;td&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="text-align: right"&gt;&lt;font style="font-size: 10pt"&gt;0.16 &lt;/font&gt;&lt;/td&gt;
    &lt;td nowrap="nowrap"&gt;&lt;font style="font-size: 10pt"&gt;%&lt;/font&gt;&lt;/td&gt;
    &lt;td style="text-align: right"&gt;&amp;#160;&lt;/td&gt;
    &lt;td&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="text-align: right"&gt;&lt;font style="font-size: 10pt"&gt;0.16 &lt;/font&gt;&lt;/td&gt;
    &lt;td nowrap="nowrap"&gt;&lt;font style="font-size: 10pt"&gt;%&lt;/font&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;
&lt;p style="font: 10pt Times New Roman, Times, Serif; margin: 0; text-indent: 0.5in"&gt;&amp;#160;&lt;/p&gt;

&lt;p style="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify"&gt;All warrants issued by the Company other than the above noted warrants
are classified as equity. For the three months ended June 30, 2013 and 2012, the Company recognized a change in the fair value
of the warrant liability of $0 and $911,922, respectively. For the six months ended June 30, 2013 and 2012, the Company recognized
a change in the fair value of the warrant liability of $0 and $1,499,852, respectively.&lt;/p&gt;

&lt;p style="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify"&gt;&amp;#160;&lt;/p&gt;</NonNumbericText><FootnoteIndexer /><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat></Cell></Cells><ElementDataType>nonnum:textBlockItemType</ElementDataType><SimpleDataType>na</SimpleDataType><ElementDefenition>Custom Element.</ElementDefenition><ElementReferences>No definition available.</ElementReferences><IsTotalLabel>false</IsTotalLabel><UnitID>0</UnitID><Label>Note 10 - Change in Fair Value of Warrant Liability</Label></Row></Rows><Footnotes /><IsEquityReport>false</IsEquityReport><ReportName>Change in Fair Value of Warrant Liability</ReportName><MonetaryRoundingLevel>UnKnown</MonetaryRoundingLevel><SharesRoundingLevel>UnKnown</SharesRoundingLevel><PerShareRoundingLevel>UnKnown</PerShareRoundingLevel><ExchangeRateRoundingLevel>UnKnown</ExchangeRateRoundingLevel><HasCustomUnits>true</HasCustomUnits><IsEmbedReport>false</IsEmbedReport><IsMultiCurrency>false</IsMultiCurrency><ReportType>Sheet</ReportType><RoleURI>http://daisanalytic.com/role/ChangeInFairValueOfWarrantLiability</RoleURI><NumberOfCols>1</NumberOfCols><NumberOfRows>2</NumberOfRows></InstanceReport>
