I wouldn't do that. Most palms don't like to have their roots disturbed. Depending on the size of the plant, I would hose all of the soil off the rootball, and then carefully tease the roots apart taking care not to break any roots. This may be difficult in larger plants, but if it is a 3 gallon or less, it should be fairly easy.

i wouldnt even try it at all to be honest. Why risk it? Once you separate the roots, they will likely go into transplant shock and even if they recover, it will be slow.

HI
Two weeks ago I separated a 3 trunk pot of spindle palms, 3-4 feet high, so far no ill effects all three look good. A few more weeks should tell. They were quite easy to separate with very minimal root damage, even if I only end up with one it will be worth it as these palm look so much better as single specimens