How do you handle selling a forum without losing members?

If you were to sell your forum how would you approach the situation of possibility losing members? Is there anything you would do first to try to de-escalate any issues like this?

I have sold forums multiple times but I have never tried to do anything to retain the members. I have seen some people export members before selling database and then upload the file so that they can have those members on a new forum. I think this is ethical practice.