Re-training
 

I am getting another GSD who has been through training at Petsmart (to intermediate level). His current owner did not keep up with his training at all. Does anyone know of any special tricks to help refresh the training he already has?

Go back and re-start to see what the dog was actually trained in. Gabor ends up doing that with a lot of client OB dogs in the area, Petsmart and other trainers.

Have him evaluated and see what he knows and they will tell you where to put him(class level)