Got it, thanks. — The message arrived. Nothing more is needed yet.
Received. Will review and get back to you. — The answer will come later, and the sender knows it is coming.
Let me look into this and circle back. — The question is accepted, and the follow-up is promised.
Thanks for your patience. — Said when an answer took longer than expected.
Just bumping this to the top of your inbox. — A polite reminder that no answer has come.