Plenty with a different role after the end of casting (6)
I believe the answer is:
galore
'plenty' is the definition.
(I've seen this in another clue)
'a different role after the end of casting' is the wordplay.
'different' indicates an anagram (letters placed in a different order).
'after' means one lot of letters go next to another.
'the end of' indicates one should take the final letters.
The last letter of 'casting' is 'g'.
'role' is an anagram of 'lore'.
'a'+'lore'='alore'
'alore' put after 'g' is 'GALORE'.
'with' acts as a link.
(Other definitions for galore that I've seen before include "Pussy ---, Bond girl" , "to spare" , "abundantly" , "Existing in great numbers" , "Aplenty" .)