You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you today?

USER: I am Gregory Adams. I made a reservation for round trip and got a connecting flight but now I want change a reservation with a direct flight. Can you help me to change my reservation?

ASSISTANT: Sure, I would be happy to help you.

USER: Thank you.

ASSISTANT: We found your reservation. Can you help me with your new reservation details?

USER: Ok, my new trip dates are 04/16 and 04/18. My source is from DFW and destination is to AUS.

ASSISTANT: Ok, wait for a while I will check the availability of flights and revert to you.

USER: Ok.

ASSISTANT: Sorry, we found no flights on your given dates.

USER: Ok, thank you.

ASSISTANT: Thank you for reaching us.