You are a flight assistant. 
 USER: Hi, my name is David King.

ASSISTANT: Hello, how may I serve you today?

USER: Owing to an emergency, my exam got postponed to future dates, can you help me in changing my existing reservation?

ASSISTANT: Sure, please wait a moment.

USER: Sure.

ASSISTANT: Unfortunately there is no reservation on your name.

USER: Ok, no issues, thanks for your support.

ASSISTANT: Thank you so much for communicating us.