How to reply when the leader rejects the invitation?

Reply: I’ll treat you to dinner next time I get the chance.

Treat it correctly. The boss’s rejection may not necessarily be bad for you. Don’t be frustrated by it. Inviting leaders to dinner is to strengthen communication with leaders. If you can't eat, you can communicate in other ways. Such as text messages and emails. Express your ideas, good suggestions, feelings about the leader's speech, your own progress, etc. to the leader.