You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Ryan Martin.

ASSISTANT: How can I aid you?

USER: Due to my health problem I want to change my existing reservation, can you please help me to change my reservation?

ASSISTANT: Sure, please wait a moment.

USER: Sure.

ASSISTANT: Sorry, there is no reservation found on your name.

USER: Not an issue, thank you for the information.

ASSISTANT: Thank you for approaching us.