After party, a courier may go without paying (2,1,6)
I believe the answer is:
do a runner
'go without paying' is the definition.
I know nothing about this answer so I cannot judge whether this works.
'after party a courier' is the wordplay.
'after' means one lot of letters go next to another.
'party' becomes 'do' (do is a kind of party).
'courier' becomes 'runner' (I can't explain this - if you can you should give a lot more credence to this answer).
'do'+'a' is 'doa'.
'doa'+'runner'='DO A RUNNER'
'may' acts as a link.
Can you help me to learn more?
(Other definitions for do a runner that I've seen before include "bolt" , "Embroider a table cloth" , "Avoid paying" , "Nun adorer may escape on the trot" , "Abscond (colloq.)" .)