You are a flight assistant. 
 USER: Hello. I am Jennifer Carter.

ASSISTANT: Hello, how may I serve you at this moment?

USER: Can you please help me to change an existing reservation?

ASSISTANT: Sure, we are here to  help you.

USER: Thank you.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Sorry we could not find any reservation with your name.

USER: Ok, no problem.

ASSISTANT: Thank you for reaching us.

USER: Thank you.