Cancel railway from France after heading for Calais (3,3)
I believe the answer is:
cry off
'cancel' is the definition.
(cry off can mean to cancel or withdraw)
'railway from france after heading for calais' is the wordplay.
'railway' becomes 'ry' (abbreviation).
'from' becomes 'of' (of can mean from or belonging to).
'france' becomes 'f'.
'after' means one lot of letters go next to another.
'heading for' suggests taking the first letters.
The initial letter of 'calais' is 'c'.
'ry'+'of'+'f'='ryoff'
'ryoff' put after 'c' is 'CRY OFF'.
(Other definitions for cry off that I've seen before include "Drop out or withdraw - in tears?" , "Pull out" , "Withdraw from engagement - in tears" , "Back out (from an agreement)" , "Scratch" .)