If there is no spoke damage, just do it. Loosen all spokes on the old wheel and then, one at a time switch each spoke to the new rim. Do not remove any spokes from the hub.

Simply place the new rim along side of the old. Ensure that your valve hole is matched to the old one and then remove a single nipple. Move the spoke into the matching spoke hole on the new rim and thread the old nipple on a wee ways(a few turns). Repeat until all spokes are fitted into the new rim. Now all you have to do is true, dish and stress relieve the wheel.

I have done this many times and without negative incident. If you do discover that there is a spoke breaking issue later on, then that is when you spring for new spokes and do it all again.

Good luck with your project.