Cash and points award- no. Not automatic. The agent must go into some system and cancel the award so the points return. I've found agents in the US know this but have always had to call back for my points if I get a abroad call center. Hate it.
I've
also had to do this exact same "call back again to get the points returned" on pure award nights (no Cash & Points) that I canceled, a time or two. They've had to fiddle with stuff and on one particular occasion I even had a PlatCon insist that the points had never been deducted in the first place! So I had to find the deduction myself on the web site and point them to it!
Didn't even think an award reservation could be made without point deduction! That particular extreme has only happened once though.
Most of the time it's automatic and no problem, however.
Just be sure to check your account right after cancellation to make sure they went back into your account, and call if they didn't.