A name to assume (3)
I believe the answer is:
don
This clue is a double definition.
'a name' is the first definition.
'assume' is the second definition.
(I've seen this before)
'to' acts as a link.
(Other definitions for don that I've seen before include "Spaniard in a University?" , "A mafia chief or Spanish grandee" , "Slip into" , "Put on clothes like noss" , "Nod off like Mafia chief" .)