Gang with influence — one can provide an opening (4,4)
I believe the answer is:
ring pull
'one can provide an opening' is the definition.
(a ring pull is used to open a tin or can)
'gang with influence' is the wordplay.
'gang' becomes 'ring' (synonyms).
'with' means one lot of letters go next to another.
'influence' becomes 'pull' (I've seen this in another clue).
'ring'+'pull'='RING-PULL'
(Other definitions for ring pull that I've seen before include "Part of a beer can" , "How to get at coke" , "Can-opener" , "Can opener" .)