What specifically are you trying to accomplish?

While you can configure freeswitch to respond to invites in a specific way, this is intended to use to terminate a call not pause it for continuation later.

Most of the SIP handing is intentionally hidden from the user with FreeSWITCH.

From: freeswitch-users-bounces@lists.freeswitch.org [mailto:freeswitch-users-bounces@lists.freeswitch.org] On Behalf Of amani mansour
Sent: Thursday, April 21, 2016 4:28 PM
To: FreeSWITCH Users Help <freeswitch-users@lists.freeswitch.org>
Subject: [Freeswitch-users] How to send Re_invite

Hi all, 

I need to configure FS to send 491 request pending message after receiving Re invite from the caller ,

The problem  that i don't know how to send the re invite request ,which xml file i whould modifie it ? please help me ,i have done many research but i didn't find anything .

Thank you ,

Best Regards 

Amani