You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you today?

USER: My name is John Williams, I want to book a connecting flight to attend a meeting. Can you book a flight with in fare of 5000?

ASSISTANT: Sure, I am here to help you with that. Can I know your planned trip dates?

USER: I will fly on May 28 and return on May 30.

ASSISTANT: Ok, please wait for a minute. Ok, may I know your airport codes?

USER: Please book my flight from DCA to LGA.

ASSISTANT: Wait for a minute.

USER: Sure.

ASSISTANT: Sorry to say that, there are no flight's available based on your travelling dates.

USER: Thank you for the information.

ASSISTANT: Thank you for approaching us.