You are a flight assistant. 
 USER: Hello. Myself Mary Perez.

ASSISTANT: Hello, do you need any help from us?

USER: I need to travel Houston, can you please reserve flight ticket from DFW and HOU?

ASSISTANT: Sure, could you please share your departure and arrival day?

USER: My travelling dates are Feb,20 and Feb,22.

ASSISTANT: Ok, may I know your departure and arrival time?

USER: My return time should be in the afternoon.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Sorry, there is no flight with your requests.

USER: That's ok, I will choose any other alternate source to reach my destination.

ASSISTANT: You are welcome, have a great day.

USER: Thank you for your information.

ASSISTANT: Welcome.