You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: I need to modify my reservation as my exams got postponed due to change in climate. Can you please help me about that?

ASSISTANT: Sure, will you please give me a moment? Please mention the name for checking the reservation.

USER: Ok, have your time. Myself William Thomas.

ASSISTANT: Thanks for waiting, there is no reservation found under your name.

USER: It's ok, anyway thank you for the information.

ASSISTANT: Welcome, have a great day.