if condition in XSLT for End of Contract date

I want to have if condition in which to use the End of Contract Date as a default value, but if it is empty or not equal the last day of work then use the actual Termination_Last_Day_of_Work?

Would you please help me on how to do that using xsl:if in XSLT?

       <End_Date>
            <xsl:value-of select="ws:Contract/ws:End_Date/text()"/>
        </End_Date>
        
        <Last_Day_of_Work>
            <xsl:value-of select="ws:Status/ws:Termination_Last_Day_of_Work/text()"/>
        </Last_Day_of_Work>

Regards, Eman