An appointment the editor dispatched for delivery (6)
I believe the answer is:
posted
'dispatched for delivery' is the definition.
The definition and answer can be both to do with social activities as well as being past participle verbs.
Perhaps you can see an association between them that I can't see?
'an appointment the editor' is the wordplay.
'an appointment' becomes 'post' (appointment to a job).
'the editor' becomes 'ed' (abbreviation).
'post'+'ed'='POSTED'
Can you help me to learn more?
(Another definition for posted that I've seen is " Mailed".)