You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I guide you today?

USER: I am James Thomas here, I want to travel from IAH to DFW, can you please help me to reserve my ticket?

ASSISTANT: I am happy to help you with that. Can you please provide your journey dates?

USER: Ok, my dates of journey is from 07/22 to 07/24. Please make sure that the price limit is 500.

ASSISTANT: Wait for a moment.

USER: Sure, take your time.

ASSISTANT: I am sorry to say that there is no flight found.

USER: Ok, no problem.

ASSISTANT: Thank you for contacting us.

USER: Thank you for your service.