Dispatched after a second agreement (6)
I believe the answer is:
assent
'agreement' is the definition.
(I know that assent is a type of agreement)
'dispatched after a second' is the wordplay.
'dispatched' becomes 'sent' (I've seen this before).
'after' means one lot of letters go next to another.
'second' becomes 's' (common abbreviation).
'a'+'s'='as'
'sent' put after 'as' is 'ASSENT'.
(Other definitions for assent that I've seen before include "Permit or approve" , "Compliance, agreement" , "Okay" , "Give the thumbs-up" , "Agree and concur" .)