You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Amy Roberts.

ASSISTANT: How may I help you?

USER: I want to change my existing reservation due to postpone of my exams, can you help me with that?

ASSISTANT: I am happy to help you, please wait a moment.

USER: Sure.

ASSISTANT: Thanks for your patience, there is no reservation found on your name to change it.

USER: No problem, thank you for the information.

ASSISTANT: Welcome Amy Roberts.