You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hi,.

USER: I am Rebecca Hill.

ASSISTANT: How may I helpful to you?

USER: As my exams were postponed, I want to change my recent reservation. Could you please help me to change my reservation?

ASSISTANT: Sure,give me a minute,I will let you know.

USER: Sure.

ASSISTANT: No reservation found on your name. Thank you for choosing our service. Have a nice day.

USER: OK, Thank you.