The deal is done and you have completed the closing.  Now what do you do?  You help the new owner because chances are that you have some vested interest in the new entity, and it is in your best interest that the new owner is successful.

For example:
– there may be an escrow account due you.
– the buyer may have given you a note.
– you may be the landlord, and the buyer the tenant.
– your name remains on the company letterhead, and your personal reputation continues to be associated with the business.
– your former employees depend on you to have made the right decision in selling to the particular buyer, thus preserving their jobs.