SIP:from-change

RFC-4916 allows From/To-URIs to change in mid-dialog requests as long as their tags stay the same, because only the tags are required for dialog identification.

innovaphone devices support this RFC in order to keep the remote party in track of changing connected party (e.g. call transfer).

Example:

 Initial INVITE from provider:
   To: <sip:+3726645340@pbx.elion.ee;user=phone>;cscf
   From: "Elo Eesmae" <sip:+3726755706@P01047948.pbx.elion.ee;user=phone>;tag=193437348

 1st re-INVITE from IP800:
   From: "Tarmo Reineberg" <sip:+3726645340@pbx.elion.ee;user=phone>;tag=1318660853
   To: "Elo Eesmae" <sip:+3726755706@P01047948.pbx.elion.ee;user=phone>;tag=193437348

 2nd re-INVITE from IP800:
   From: "Tarmo Reineberg" <sip:+3726645340@pbx.elion.ee;user=phone>;tag=1318660853
   To: "Elo Eesmae" <sip:+3726755706@P01047948.pbx.elion.ee;user=phone>;tag=193437348

 3rd re-INVITE from IP800:
   From: "Tarmo Reineberg" <sip:+3726645340@pbx.elion.ee;user=phone>;tag=1318660853
   To: "Elo Eesmae" <sip:+3726755706@P01047948.pbx.elion.ee;user=phone>;tag=193437348

 4th re-INVITE from IP800:
   From: "Risto Kiilberg" <sip:sip.P00236306@pbx.elion.ee>;tag=1318660853
   To: "Elo Eesmae" <sip:+3726755706@P01047948.pbx.elion.ee;user=phone>;tag=193437348

 5th re-INVITE from IP800:
   From: "Risto Kiilberg" <sip:sip.P00236306@pbx.elion.ee>;tag=1318660853
   To: "Elo Eesmae" <sip:+3726755706@P01047948.pbx.elion.ee;user=phone>;tag=193437348