You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello.

USER: I am Matthew Hill.

ASSISTANT: By what way, can I assist you now?

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

ASSISTANT: Ok, I will aid you. Sorry, there was no reservation on your name.

USER: Ok, no issues.

ASSISTANT: Thank you for picking us.

USER: Thanks for your service.

ASSISTANT: Have a good day.