You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I guide you today?

USER: I am Janet Hernandez. Actually I planned a trip to DTW, but my travel dates have been postponed. Can you change my reservation.

ASSISTANT: Sure Janet, I am here to help you, wait a moment.

USER: Ok.

ASSISTANT: Thank you for waiting, there is no ticket exist in our data base on your information.

USER: It's fine. Thank you for your immediate response.

ASSISTANT: Thank you for your approach Janet. Have a nice day.

USER: Thank you.