You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you?

USER: I am Gary Wilson. I have reserved my flight ticket with wrong dates, can you please change my existing reservation?

ASSISTANT: Sure, I will help you to change your existing reservation. Can you please provide me your travelling dates?

USER: My travel dates are 07/09 and 07/11.

ASSISTANT: Ok, may I know your airport codes?

USER: My trip codes are BOS - SEA.

ASSISTANT: Ok, give me a moment.

USER: Ok.

ASSISTANT: Sorry, there is no flight is found for your requested dates.

USER: Ok, please proceed. Ok, fine thank you for your help.

ASSISTANT: Welcome.