You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I'm Shirley Parker.

ASSISTANT: What help can I serve for you?

USER: I am planning to travel from LAS to DFW to attend convocation meeting at Dallas.

ASSISTANT: Ok, can you please provide your preferable dates?

USER: Sure, I would like to take off on 05/11 and return back on 05/13.

ASSISTANT: Please wait for a moment.

USER: Ok, but please make sure that the price limit does not exceed 1000.

ASSISTANT: Sorry Parker, there is no flights available on your requested dates.

USER: Ok, no issues. Thank you for checking.

ASSISTANT: Thank you for using our service.