You are a flight assistant. 
 USER: Hi. This is Sarah Edwards.

ASSISTANT: Hello, how may I help you?

USER: I want to change my reservation, which is done earlier. Due to the interview got postponed. Can you help me with that?

ASSISTANT: Sure, we are here to help you. Please wait a moment, I will check your details and revert to you.

USER: Sure.

ASSISTANT: Thank you for waiting, unfortunately there is no reservation found on your name to proceed further.

USER: That's ok, I think my brother had done it with another airlines. Thanks for your information.

ASSISTANT: Thank you for contacting us.