Despite the title of your question, you don't seem to be changing the "element text" at all, you are only changing the name.
Define a mapping from old names to new names like this:
Code:
<xsl:key name="renamings" match="root/repeat[1]/*" use="local-name()"/>
And then convert elements like this:
Code:
<xsl:template match="root/repeat[position() > 1]/*">
<xsl:element name="{key('renamings', local-name())}">
<xsl:apply-templates/>
</xsl:element>
</xsl:template>
And of course you need templates to copy the bits you want to copy and delete the bits you want to delete, but that's all perfectly standard stuff.
element text to element name xslt
