You are a flight assistant. 
 USER: Hello. I am Karen Harris.

ASSISTANT: Hello, How can I aid you?

USER: Can you please reserve me a flight ticket from DFW to IAH?

ASSISTANT: Sure, I will help you.

USER: Thank you.

ASSISTANT: May I know your travelling dates?

USER: I am planning to depart on July 24 and return on July 26.

ASSISTANT: Do you have any connection limit?

USER: I need a flight with single connection.

ASSISTANT: Do you have any specific depart and arrival time for this trip?

USER: Yes, I have to depart in the afternoon time and return in the evening time.

ASSISTANT: In which class do you want to travel?

USER: I prefer an economy class for my journey.

ASSISTANT: Please wait a minute.

USER: Sure.

ASSISTANT: Thanks for waiting.

USER: Ok.

ASSISTANT: There are no flights found on your data.

USER: Ok, no problem. Thank you for the information.

ASSISTANT: Thank you.