You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, which service are you seeking for today?

USER: Myself David Smith, I am willing to travel this weekend to meet my friend's at Dallas. Can you please help me in reserving the ticket from HOU to DFW?

ASSISTANT: Sure, we are mirthful to help you. On which dates would you like me to book a flight ticket for you?

USER: I am willing to travel on Dec 01 and again I will return back on Dec 03.

ASSISTANT: Ok, Do you have any class preference?

USER: My class preference is economy class.

ASSISTANT: Do you like to go with a connecting or direct flight?

USER: I mostly prefer for single connection.

ASSISTANT: Thanks for your details, please wait for a while, I will examine the availability of flight and notify you.

USER: My airline preference is normal cost.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Thank you for waiting, sorry to inform you that unfortunately there is no flights available by the given details.

USER: Not a big deal, anyway thank you very much for your service.

ASSISTANT: Thanks for approaching with us.