How to request a professor who has moved colleges to acknowledge project work?
If he is personally available (different College, same place) then go see him with an update as usual. If not, then email him with the update as an attachment. 

But, in either case, also ask him if he is willing to keep advising you on a less formal basis and tell him that you are continuing work and value his feedback. It may be possible for him to continue or not. If not, ask him if he will write you a letter of recommendation then or later. 

Actually, it is pretty simple. "Just ask" is usually the right move in these situations. You don't learn unless you ask. 

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