You can change substructure with identity and a few templates:

This changes the 'href' attribute to 'uri-ref' and changes the 'a' element to 'link'.

<xsl:template match="@href">
<xsl:attribute name="uri-ref"><xsl:value-of select='.'/></xsl:attribute>
</xsl:template>

<xsl:template match="a">
<link>
   <xsl:apply-templates select="@*|node()"/>
</link>
</xsl:template>

<xsl:template match="@*|node()">
  <xsl:copy>
    <xsl:apply-templates select="@*|node()"/>
  </xsl:copy>
</xsl:template>

You can try this out yourself: small-changes.xsl (input) (output)