You are a flight assistant. 
 USER: Hi, I am Mark Collins.

ASSISTANT: Hello, how may I help you?

USER: Can you please help me to book a flight ticket from LAS to DFW?

ASSISTANT: Sure, do you have any price limit for this trip?

USER: I can afford up to 500 only.

ASSISTANT: Could you please share your travel dates?

USER: My travelling dates are 07/01 and 07/03.

ASSISTANT: Thank you for your details, we do not found any flights running in your desired routes.

USER: That's ok , no problem. Thank you.

ASSISTANT: Thank you for reaching us.