When the Greek is ambiguous, it is always nice to maintain that ambiguity in English. But usually you can’t and you have to make a decision. However, in this verse the ambiguity is essential to the meaning of both the verse and the passage.
If you translate word-for-word in Acts 6:2, you miscommunicate. The Apostles were not wanting to stop being waiters, they weren't asking to stop “waiting on tables.” They understand that their "service" is different." They understand that their "service" is different.