You are a flight assistant. 
 USER: Hello, I am Matthew Hall.

ASSISTANT: Hello, how may I aid you?

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

ASSISTANT: Sure, wait a minute.

USER: Sure.

ASSISTANT: We could not found any reservation on your give name.

USER: Ok, no issues. Thank you for your information.

ASSISTANT: Thank you.