Dogs, if given clear and consistent rules, can get used to just about anything. So when my dogs jump on the couch and Ike tries to follow their lead, I kindly tell him "off," and then offer him another comfortable spot.
The picture on the left shows "Ike's couch." It's our fireplace hearth with an outdoor cushion. It's right next to the real couch and it's almost the same height. It's not the real couch, but Ike doesn't need to know that. All he needs to know is that it's his and it's acceptable.
Sometimes Ike voluntarily gets onto his couch. He gets lots of calm praise for that and he then promptly goes to sleep.
What's important to note is that we're teaching Ike an appropriate alternative behavior from the beginning. That's very different than trying to re-train Ike to stay off the couch. Many of my clients let their dog onto the furniture when the dog was a pup, but then decide they don't want the dog on once he gets bigger.
That's not really fair to the pup, and it's ridiculously hard on the owner to teach the new rule to the dog. It would be a lot like your coming home and the locks on the doors have been changed. No one warned you that you key would no longer work, no one gave you the new key, and now it's up to you to figure out how to get in. That's just not fair!
We knew from the minute Ike walked in that we'd have a little harder time teaching him to stay off the furniture because our guys are allowed. We had our plan in place (the alternate couch), and ensured that the boundaries were clear — and consistent — from the very beginning. And the best part – all the dogs are happy and we're living within the rules of the service dog organization!