Son in law and daughter have lived with me for 6 years. Want to evict son-in-law as they are goint to get a divorce.

IF they rented as a couple - at least in NY - they have to evicted as a couple. The "secret," of course, is that your daughter doesn't actually move out.

Here is a good reference site for the procedure - it's a private site paid for by an Attorney. I am not recommending her in any way but the information is plainly stated and easy to understand.

(I can't IMAGINE living with a couple in the process of divorce.)