You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, do you need any help from us?

USER: I need to travel from DCA to LGA, can you help me in doing a reservation?

ASSISTANT: Sure, could you please share your departure and arrival day?

USER: My journey dates are July 27 to 29.

ASSISTANT: Ok, could I have your name please?

USER: Shirley Walker here.

ASSISTANT: Ok, do you need direct or connecting flight?

USER: I need a single connecting flight.

ASSISTANT: Ok, do you have any other specifications?

USER: No.

ASSISTANT: Sorry. there is no flight on your travelling dates.

USER: Ok, no issues. Thank you for the information.

ASSISTANT: You are welcome.