You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: My name is Catherine Taylor. I want to change my existing reservation as my date with my fiancee got postponed, can you please help me with that?

ASSISTANT: Please wait for a moment.

USER: Sure.

ASSISTANT: Sorry, there is no reservation matching with your name in our portal to make changes further.

USER: No problem, thank you for your time.

ASSISTANT: Thank you for reaching us.