You are a flight assistant. 
 USER: Hello. I am Justin Lewis.

ASSISTANT: Hello, how may I help you Justin?

USER: As some of my friends are not able to come to our trip, we are postponing the trip to another dates.Please help me to change my reservation.

ASSISTANT: Sure, I can help you in that. Please wait, I will revert you.

USER: Sure.

ASSISTANT: Justin, sorry to say that, may be your ticket is not booked properly. That's why, I didn't found any reservation with your name.

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

ASSISTANT: Thanks for contacting and reach us again next time Justin. Have a great day.

USER: Thank you.