You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I assist you?

USER: I want a direct flight, so book a ticket under name of David Lewis.

ASSISTANT: Sure, may I know your price limit?

USER: Make sure that price limit should not exceed 200.

ASSISTANT: Ok, may I know your journey dates?

USER: My journey dates are from 05/10 to 05/12.

ASSISTANT: Ok, can you please assign your journey airport codes?

USER: My airport codes are from PHL to DFW.

ASSISTANT: Thanks for providing, please wait.

USER: Ok.

ASSISTANT: Sorry for inconvenience, we did not find any flights under the price limit of 200.

USER: Ok. Thank you for quick response.

ASSISTANT: Thank you for reaching us.