Before sending this message I looked for an answer and found some options, two of them are followed: 1) SUBST function, sample listed here: if (is_present_hf("User-Agent")) { remove_hf("User-Agent"); remove_hf("P-Asserted-Identity"); subst("/^From: \".+\" (<sip: *[a-zA-Z0-9_\.-]+ <at> .*>)/From: \1/ig"); subst("/^To: \".+\" (<sip: *[a-zA-Z0-9_\.-]+ <at> .*>)/To: \1/ig"); } 2-a) uac_replace: if (from_uri=~"^sip:10804007\@voip.mydomain") { xlog("L_ALERT", "TESTANDO - Original From is ($fu-$fn)\n"); # uac_replace_from("sip:031" . $fU . "\@voip.mydomain"); uac_replace_from("Frota10804007","sip:03110804007@voip.mydomain"); xlog("L_ALERT", "TESTANDO - From changed to ($fu-$fn)\n"); }; OR : 2-b) uac _replace #2: if (from_uri=~"^sip:10804007\@.*") { xlog("L_ALERT", "Route 21 - Original from is ($fu-$fn)\n"); $avp(from)=$fu; # $avp(to)=$ru; # avp_pushto("$ru", "$avp(from)"); avp_subst("$avp(from)", "/(sip:)/sip:031/"); uac_replace_from("$avp(from)"); # xlog("L_ALERT", "Route 21 - From changed to ($fu-$fn)\n"); # avp_pushto("$ru", "$avp(to)"); }; } OR Looks like uac_replace is safer then "subst" function, because it can be reverted, but I did not found a way to use concatenation or any other kind of string operation as a parameter for it. I don't want to start a discussion, I need only a few lines showing me how to change from_uri_from from "sip:108xxxx" to "sip:031108xxxx". Thanks in advance, -- Fernando Frota Machado de Morais Divisao de Redes de Comunicacao Centro de Computacao Universidade Federal de Minas Gerais Brasil Tel. +55(31)3409.4007 Fax. +55(31)3409.4004