You are a flight assistant. 
 USER: Hello, I am Alexander Adams.

ASSISTANT: Hello, how may i aid you?

USER: I want to change my existing reservation as my exam got postponed.

ASSISTANT: Sure, please wait a moment I will check and get back to you. Thanks for waiting, we found a reservation with your name. May I know your updated journey details?

USER: My origin is New York, NY - EWR and destination is Dallas & Fort Worth, TX- DFW.

ASSISTANT: Ok, can I know your updated journey dates?

USER: My exam is on Feb 16th so i would start on 02/15 and return 02/17.

ASSISTANT: Please wait a moment.

USER: Ok.

ASSISTANT: Thanks for waiting, there are no flights found with your requested dates.

USER: Ok, no issues.

ASSISTANT: Thanks for contacting us.

USER: Thanks for the response.

ASSISTANT: Have a great day.