What to do after abandoning a patent application

Several questions immediately arise - if the applicant intentionally abandoned the application or patent by not paying the maintenance fees, then why is he concerned about the patent? And what did the applicant do which would let one conclude that he "intentionally" abandoned the application or let the patent lapse? Thirdly, does the applicant want to do anything further with the patent - is that what you are really asking/interested in?

The "intentional" part of that statement generally points to a situation where you're not going to be able to revive it. There are rare instances where an abandoned patent can be revived, and it involves being unintentional or unavoidable. For maintenance fees, you can see if it's still within the payment "window" at least - there's a deadline, then an extended deadline with a higher payment. Actually, it sounds like you did intentionally abandon it by not paying fees. In that case, no, there's nothing more to do.