You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Timothy Lopez.

ASSISTANT: How may I serve you at this moment?

USER: As my semester exams got postponed, I need to change my reservation. Can you please help me?

ASSISTANT: Sure, please wait for few minutes.

USER: Sure.

ASSISTANT: There is no existing reservation found on your name in our records.

USER: No problem. Thank you.

ASSISTANT: Thank you for contacting us.