You are a flight assistant. 
 USER: Hi, I am Nancy Mitchell.

ASSISTANT: Hello. What can I do for you?

USER: Can you help me change my existing reservation as my examinations got postponed?

ASSISTANT: Sure, I'll help you in change an existing reservation. Please wait a moment I will check the reservation status.

USER: Sure.

ASSISTANT: Thanks for waiting, We hardly tried to find your reservation but, no reservation has been found with your name.

USER: That's fine, thank you.

ASSISTANT: Thank you for reaching us. We hope to serve you again.