Doors will not lock or unlock with remote

There is no reset that does not involve a factory style scan tool. If all remotes stopped working there are a couple modules that could have failed and testing them requires the scan tool as well to watch if they respond to the remotes. If you bought it used from a dealer take it back and have them test it, should be at least a warranty that long on it.
If you bought it privately then you are sort of stuck.

Do the interior buttons work? that would verify if it is the BCM or door modules that were at fault.

Interior buttons work.

Okay, then it has to be in the actual remote system. They can be hard to track. You might find an automotive locksmith. Most have ways to test and verify operation of the remotes and can try re-programming. Usually for a lot less than a dealer and you normally can just show up with no appointment.
That might narrow it down some.

Thank you Steve, I really appreciate it.

You are welcome. Keep us in the loop as to what you find out. Some of these vehicles have sparse information available as to the actual repairs for faults.