Convenient rewriting of panto (2,3)
I believe the answer is:
on tap
'convenient' is the definition.
(thesaurus)
'rewriting of panto' is the wordplay.
'rewriting of' is an anagram indicator.
'panto' anagrammed gives 'ON TAP'.
(Other definitions for on tap that I've seen before include "Of liquid gas, ready to be drawn off" , "Where to find a washer" , "Immediately available like beer in pub" , "Available (for drinking?)" , "where C or H is seen?" .)