Have and have influence (7)
I believe the answer is:
possess
I believe this clue is a triple definition!
'have' is the first definition.
(I know that have can be written as possess)
'and' is a link.
'have' is the second definition.
(possessing is a kind of having)
'influence' is the third definition.
(I know that possess is a type of dominate)
(Other definitions for possess that I've seen before include "Have ownership of" , "Consume" , "influence" , "Own, keep" , "Have and hold" .)