You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am John Smith.

ASSISTANT: How may I serve you at this moment?

USER: I am planning to travel from DFW to CLT, help me in booking a flight?

ASSISTANT: Sure, do you need any stopover in between the journey?

USER: My travelling dates are Jan 13 to 15.

ASSISTANT: Ok, may I know your class preference?

USER: I am comfortable in any class.

ASSISTANT: Ok, do you have any other preferences?

USER: I want to departure in evening and I will be return in morning.

ASSISTANT: There are no flights found on your required specifications.

USER: That's ok, thank you.

ASSISTANT: Thank you for reaching us.