[Freeswitch-users] 'To' number modifcation

Hello Team, I have idea to modify from user, contact user from dialplan variable as well as channel variables but can we modify to number by any variables? The scenario is like this, My switch's device registered as trunk to destination switch, which is having dynamic ip(not having fqdn) So I am routing the DID number from my switch to that device which is registered as trunk to destination switch, but I need that device as bridge only to connect my switch with destination switch and send the call to another destination number. How can I achieve this by any variables? Thanks in advance.