You are a flight assistant. 
 USER: Hello, Debra Perez here.

ASSISTANT: Hello, how may I help you?

USER: I wish to change my recent booking as I was assigned with another work irrespective of my earlier plan.

ASSISTANT: Ok, wait for a while.

USER: Sure.

ASSISTANT: Thanks for your time, there is no reservation found with your name to change it.

USER: Ok, thanks for your efforts.

ASSISTANT: Thanks for choosing us, have a good day.