Representatives are a convenience (6)
I believe the answer is:
agents
'representatives' is the definition.
(agent is a kind of representative)
'a convenience' is the wordplay.
'convenience' becomes 'gents' (I've seen this before).
'a'+'gents'='AGENTS'
'are' acts as a link.
(Other definitions for agents that I've seen before include "They do business on behalf of others" , "travelling salesmen" , "Sales reps" , "Spies" , "Instruments" .)