Learn English – n antonym for “delegate”

I am trying to find the correct opposite of a delegate in the context of a person being a representative of someone else that have allowed or chosen them to be their delegate.
What would you call that "someone else?"
The only word I could find is a delegator (which isn't a real word in English) or assigner, but they are technical words rather than descriptive.

Any other word I could use?

Think of it in a sentence like this:

Here is a list of all the delegates in the company.
But that is the list of their _ _ _ _ _ (what can go here?).

I am trying to avoid fillers such as: bosses, agents, managers, etc.