xsl:namespace-alias

<xsl:namespace-alias
   stylesheet-prefix = "prefix"
   result-prefix     = "prefix" />

The top-level xsl:namespace-alias element declares that one namespace URI in the stylesheet should be replaced by a different namespace URI in the result tree. Aliasing is particularly useful when transforming XSLT into XSLT using XSLT; consequently, it is not obvious which names belong to the input, which belong to the output, and which belong to the stylesheet.