You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Sarah Walker.

ASSISTANT: Sarah, how may I help you?

USER: I had planned to go on a trip, but it was postponed due to some reasons. Can you change my recent reservation?

ASSISTANT: I will do that for you, I need to check your reservation status first.

USER: Ok, take your time.

ASSISTANT: Sarah, I did not find any reservation on your name in our database.

USER: That's ok. Anyways, thank you.

ASSISTANT: You are welcome and thank you for choosing us.