You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: Can you help me in changing my recent reservation, as my exam is postponed?

ASSISTANT: Sure, may I know your name?

USER: Check under the name Charles Martin.

ASSISTANT: Thank you. Please wait, let me check your reservation status.

USER: Sure.

ASSISTANT: Sorry, no reservation found under your name in our database.

USER: That's ok, thank you.

ASSISTANT: You are welcome and thank you for choosing us.