emend means in slang: 1. You can make amends by sending an email, particularly if you are applying The 9th Principle of Alcoholics Anonymous’s 12 Step Program.

2. Emails can be used to apologize or attempt to correct a mistake.
(in Slang Dictionary, added by Ricardo Moreno)

What else does emend mean?

Critical editing is a way to improve.
(in Merlin Dictionary)