You cannot change the caller id information sent on a per user/extension basis. You can, however, change it from sending out the DID information to sending out the main number for all calls. This is done under PRI programming number to send. It is probably set up now as "base number plus extension". You would need to change it to "line number" and then enter the first PBX line number of the T1(801, 802, etc) depending upon where the T1 module is located. At that point it will ask you to enter the number to send for that specific trunk. You must physically enter the main number (xxxxxxxxxx)in for each of the PRI channels/trunks seperately.