I went away for 12 days and wondered how this would affect Kili's tricks and training. Interestingly I found that she shed some bad habits in training when I returned. I had her on free feed while gone so she was way over training weight when I returned. She was motivated to do some training but not as much as she would do when actually hungry. So I'd say the break reduced food based motivation and endurance. But it increased non-food motivation just out of desire to do something fun/habitual.
Also I was surprised to find her do old tricks with better accuracy than before I had left. This isn't the first time I noticed this and I've even noticed the same apply to myself. The good habits have a longer history of training but the bad habits come along in training when the bird is poorly motivated or just goofing off. The lucky thing is that there is a longer history of the parrot doing the right rather than wrong things so that is what comes back from memory after a break in training. For instance before I left, she was getting into a lazy habit of flying back to the mid-room perch rather than the perch at the end of the room as she had normally done in training. But when I got back, she had every opportunity to go to the close one but flew to the far one out of habit. After several days the laziness started coming back but the immediate after-return effort was good. She only forgot or got the cue for flip confused but that is one of the most recent tricks I'd taught her. So it only took a few attempts at teaching the trick over again for her to re-calibrate the cue to the behavior.
My point is that it's ok to take a break from training once in a while and don't worry about them forgetting tricks that they know solid. Forgotten ones can be quickly retaught. The break can even be beneficial and rekindle an enthusiasm for training both for owner and parrot. So enjoy a vacation and don't worry about your parrot forgetting tricks it knows.