XSL Stylesheet how to use "and / or" in replace

On the variable "urgent", I have put a "replace" on it, so if the string in the variable are "Urgent - 2 arbejdsdage" its changes it to "YES". But if the string are "Overnight" it must also changes it to "YES", can i put a "or" in the style, or must I use "xsl:if" How can i do it ?

    <variable name="urgent">
                    <xsl:variable name ="urgent" select="OrderCustomReferences/CustomReference/ReferenceValue"/>
                    <xsl:text disable-output-escaping="yes">&lt;![CDATA[</xsl:text>
                    <xsl:value-of select="replace($urgent, 'Urgent - 2 arbejdsdage', 'Yes')"/>
                    <xsl:text disable-output-escaping="yes">]]&gt;</xsl:text>
                </variable>