Dear list, I'd like to rewrite the number in the Remote Party ID header and only in this header. ex: I'd like to prefix the caller ID with a prefix code (000 in this example) in the RPID header : From: Anonymous<sip:anonymous@anonymous.invalid>;tag=1208367 Remote-Party-ID: <sip:123456@10.10.10.10:5062;user=phone>;privacy=full;screen=yes;party=calling should become: From: Anonymous<sip:anonymous@anonymous.invalid>;tag=1208367 Remote-Party-ID: <sip:000123456@10.10.10.10:5062;user=phone>;privacy=full;screen=yes;party=calling But the From field should remain unchanged. And how to strip this prefix: From: Anonymous<sip:anonymous@anonymous.invalid>;tag=1208367 Remote-Party-ID: <sip:000123456@10.10.10.10:5062;user=phone>;privacy=full;screen=yes;party=calling should become: From: Anonymous<sip:anonymous@anonymous.invalid>;tag=1208367 Remote-Party-ID: <sip:123456@10.10.10.10:5062;user=phone>;privacy=full;screen=yes;party=calling regards.