I don't suggest messing with any loan documents. Instead, place a memo in the individual's credit file concerning the name change. Any future loans to that individual should reflect the new name. You can update computer records so that billing, notices, etc., are generated correctly.
As for deposit accounts, if the individual is going to sign his/her name differently, it's a good idea to get an updated signature card if it's possible. That might be a challenge if it's a joint account, but you need to have an updated signature for comparison purposes.