Is there any way in which i can rewrite the From header efficiently

like i want to change this From header
From: "Zeeshan"<sip:shani@localhost.localdomain>;tag=4a6dec6f
to
From: "Zeeshan"<sip:shani@128.242.111.222:5060>;tag=4a6dec6f

how can i do that using subst  function ???? please help me thanks in advance
regards

Zeeshan

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