You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, may I know your name?

USER: Due to change in trip I want to change my existing reservation.

ASSISTANT: Ok. Please tell me your name.

USER: My name is Benjamin Evans.

ASSISTANT: I found reservation for you. Please give me your journey details.

USER: I am travelling from ATL to JFK. Travel dates are 04/13 to 04/15.

ASSISTANT: There is a flight for you from Frontier airline with number 1008. Shall I book the ticket?

USER: Ok, please book the ticket.

ASSISTANT: Your ticket has been booked.

USER: Great service. Thanks for helping me out.

ASSISTANT: Thank you for choosing our service.