You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I want to change my existing reservation, as my exams got postponed suddenly. Can you please help me to change?

ASSISTANT: Can you please provide the name on which the reservation is confirmed?

USER: Rebecca Edwards.

ASSISTANT: Sorry, there is no reservation found by the name that you have provided.

USER: Ok, no problem.

ASSISTANT: Thank you and have a nice day.