Opted to change store (5)
I believe the answer is:
depot
'store' is the definition.
(depot can mean a store or warehouse)
'opted to change' is the wordplay.
'to change' indicates an anagram.
'opted' anagrammed gives 'DEPOT'.
(Other definitions for depot that I've seen before include "Regimental HQ" , "Bus station or warehouse" , "storeroom" , "Storehouse, repository" , "Storehouse as for supplies" .)