Ask somebody there - ideally, your resort Manager (who has the capability to make the change) but you can start with a cashier. They may be currently able to allow you to get a couple of snacks instead of a CS meal, without management approval.
Other than that, the only official swap is the use-TS-for-CS+snack(s)-or-sling-bag. The point of THAT swapability is, Guests are unable to use their TS credits due to not having reservations.
There's no corresponding 'problem' with CS locations, so there's no official swap policy.