You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I assist you?

USER: I am Shirley Miller, want to travel from LGA to IAD. Please help me in booking my flight ticket.

ASSISTANT: Sure, I am here to help you out. May  know your travelling dates please?

USER: Thanks and my travelling dates are from 03/18 to 03/20.

ASSISTANT: Wait a moment please.

USER: Sure.

ASSISTANT: Shirley Miller, there are no flights available in your route.

USER: It's ok, thank you for your help.

ASSISTANT: Thank you for reaching us.