Do you allow users to use 7-digit dialing or do all outbound calls use 10-digits? (I'm assuming you are in the US or Canada.) Also, a brief idea of what kind of partitions and route pattern you have would help.

You probably have a 9.1XXXXXXXXXX route pattern for LD calls and probably a couple 9.NNNXXXXXXX route patterns (where NNN is the local area code). If you want the remote users phone to be normalized for the area it's in (i.e. no 1 for local area codes, 1 required for calls to the HQ area code), you will need to move the 9.NNNXXXXXXX route pattern into a different partition that is not in the remote users Calling Search Space. You will also need to create one or more 9.NNNXXXXXXX route pattern(s) for the remote users local area code(s) and place those in a partition that is listed only in the remote users Calling Search Space. Also, you will need to prepend a 1 on those route patterns in order to get the proper LD treatment when you pass the calls to the PSTN.

All of those also assumes that you use a 9 access digit for outside calls.