You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Donald Moore.

ASSISTANT: How may I support you today?

USER: Unfortunately my exams was got postponed so I want to change my reservation, can you help me to change my reservation?

ASSISTANT: Sure, give me a moment I will check the reservation list.

USER: OK.

ASSISTANT: Thanks for waiting, unfortunately there is no reservation found by this name.

USER: Ok, no problem.

ASSISTANT: Thanks for availing us.

USER: Thank you.