Only the state (and a few odd cases like the federal government) manufacture plates in the US, and they usually don't have a published process exactly for obtaining a new plate when you already have one. That said, my experience in a couple of states is that DMV clerks have no problem putting in a plate as lost/damaged/stolen if you just ask for a new one. The fee where I live today is only $15, but I live in a poor state, Maryland might be steeper.