You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am John Carter.

ASSISTANT: How may I be of your assistance?

USER: I want to change my recent reservation, due to health issue. Can you help me in my changing reservation?

ASSISTANT: Sure.

USER: Ok.

ASSISTANT: Please wait a moment I will check the reservation status.

USER: Sure.

ASSISTANT: Thank you for waiting, we did not found any reservation by this name.

USER: Not an issue.

ASSISTANT: Thank you for availing us.

USER: Thank you for your quick response.