You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you now?

USER: I am Timothy Thompson. Due to my health problem I want to change my reservation, can you please help me that?

ASSISTANT: Sure, I will help you. Please, wait a  while.

USER: Ok.

ASSISTANT: Thanks for your time.

USER: No problem.

ASSISTANT: We did not find any reservation on your name.

USER: Ok, that's not a problem. Thank you.

ASSISTANT: Thank you for approaching us.