You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello.

USER: I am Nicholas Hall.

ASSISTANT: How may I aid you today?

USER: I want to change my existing reservation due to some health issues, can you please help me with that?

ASSISTANT: Sure, please wait a moment I will check and revert to you.

USER: Sure.

ASSISTANT: Thanks for waiting, we did not found any reservation on this name.

USER: Ok, no issues.

ASSISTANT: Thanks for choosing us.

USER: Thanks for your help.