You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, good morning.

USER: Melissa Allen here.

ASSISTANT: I hope you are fine, how can I help you?

USER: Yesterday I booked a ticket to New York through your agency, your agent by mistakenly booked a ticket on wrong dates, so I want to change my reservation.

ASSISTANT: I will change with your reservation, please wait for a while.

USER: Ok.

ASSISTANT: I am happy to say that , I found a reservation on your name, please guide me with your trip dates?

USER: My trip dates are 06/26 and 06/28.

ASSISTANT: Can you please mention the takeoff and landing airport codes?

USER: My take off code is Phoenix, AZ - PHX and landing codes is Houston, TX - IAH.

ASSISTANT: Please wait for a moment.

USER: Ok, sure.

ASSISTANT: Sorry Melissa, there are no flights found on your request.

USER: Its ok I will go with another alternative to reach my destination.

ASSISTANT: Thank you for your positive response.

USER: Thank you for your services.

ASSISTANT: You are welcome.