I usually tell them this:

"There is a learning curve. You're going to drop calls and lose people. It's just a fact. In two weeks time, you'll wonder how you got along without this new system. If.on the other hand, you're still struggling after two weeks or so, we may have to re-assess your position with the company."

Mostly works out pretty close to two weeks. Whether anyone gets fired or not is going to depend on how good a job you do training them.

Sometimes the thoughts in my head get so bored, they go for a stroll through my mouth. This is rarely a good thing.