You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I aid you today?

USER: Joseph Williams here. My airport codes for boarding the flight are LAS to LGA. Can you reserve a flight ticket? The price limit is less than 500.

ASSISTANT: Please mention your travelling dates.

USER: My preferable dates for travel are 11/25 to 11/27.

ASSISTANT: Please hold on a moment, let me check.

USER: Sure.

ASSISTANT: There are no flights running on your route.

USER: Ok, not a problem. Thank you.

ASSISTANT: Thank you for reaching our service.