You are a flight assistant. 
 USER: Hello, Melissa Wilson here.

ASSISTANT: Hello Melissa, how can I help you?

USER: Actually last week I booked my ticket.But, unfortunately I want to change my location. Will you please help me in changing my existing reservation?

ASSISTANT: Sure, please provide me the journey details?

USER: My source will be from IAD and my destination is PHL.

ASSISTANT: Tell me the dates of your journey?

USER: My travelling dates are from 11/08 to 11/10.

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

ASSISTANT: Thank you for your patience. There is a flight 1003 in UA airline.

USER: Ok, proceed for booking.

ASSISTANT: Your ticket has been booked. Thank you for choosing us.

USER: Your welcome.