Hmm,
the idea of the plugin isn’t really for usage as an internal ordering system so to speak but to allow customers to order things over the/your website for delivery or self-pickup, in which case everything WOULD be ordered at once (and just one bill would need to be printed).
Nor is the scope of it to be a table reservation system or some such .

Bearing that in mind, I don’t think there will ever be a function that “clears the table” for the next sitting. After all, the plugin does not know anything about your tables, regardless of whether or not you just renamed a field.

However, one could think about a way to either combine various orders into one, or being able to add more items to an already existing order, either one will open another big can of worms though.
I will add this to my list of ideas, but cannot give you any ETA as to when or even if this will ever be available/implemented.

All I can say though it’s most definitely not going to happen in the next few months as I do not plan to add any additional functionality of that magnitude to wppizza v2.x
Perhaps in v3+ (which I am working on at the moment). But that’s months away yet