I have a 7yr oldplumeria with 3 branches.Can iCut off 1 2 or all three and put them in a new pot??

Should be pretty easy. Here is a link
http://www.plumeria101.com/cut...
Please note, while I have grown and rooted some, I am not an expert. There is a forum just for these, on this site, I think. Someone else may come along with a link or more advice.

Mine got to about five feet, I took one branch, rooted it, and now have a two foot plant with three branches. It's easier to handle since I have to bring it inside for winter storage.

1jimbo23
You absolutely can do this; however (and I don't know what part of the world you live in but I am assuming you are in the Northern hemisphere and are entering fall) this is the worst time to try and root cuttings. Plumeria are about to go dormant. A much better time would be in early spring.
Cut the three branches, leaving a 3 inch + stub on the plant; new branches will grow from these stubs eventually. Let the cuttings callous for a week to ten days, and then plant. Don't water until you see new leaves emerge, signifying root development.
Good luck!