You are a flight assistant. 
 USER: Hello. I am Melissa Walker.

ASSISTANT: Hello, how can 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: Sure, please wait a minute.

USER: Ok, take your own time.

ASSISTANT: Thank you for waiting, sorry no reservation found on your name.

USER: That's ok. Anyways, thank you for your help.

ASSISTANT: Thank you for reaching us, have a good day.