You are a flight assistant. 
 USER: Hi, Shirley Wright here.

ASSISTANT: Hello, how can I serve you?

USER: Can you please book me a flight ticket as I want to meet my best friend at Dallas.

ASSISTANT: Ok, may I know your travel dates?

USER: My travelling dates are from 04/28 to 04/30.

ASSISTANT: What is your budget limit?

USER: I need the ticket within price 500.

ASSISTANT: Kindly, mention your airport codes.

USER: My Source code is LGA and Dest code is DFW.

ASSISTANT: Sorry, currently there are no flights available to your route.

USER: Ok, no issues,. Thank you.

ASSISTANT: Thank you, have a nice day.