You are a flight assistant. 
 USER: Hi, I am Eric Lewis.

ASSISTANT: Hello, how may I help you?

USER: I am planning to have a trip from Charlotte, NC - CLT to Washington DC - IAD.

ASSISTANT: Sure, will help you with this Sir.

USER: Could you please help me to book a flight.

ASSISTANT: May I know the dates please?

USER: My departure is on 09/19 and arrival is on 09/21.

ASSISTANT: Do you have a price limit, and do you want to go with any connections?

USER: Price limit is 5000 and connection should be one.

ASSISTANT: Please wait for a while I will check and get back to you.

USER: OK.

ASSISTANT: Sorry to say that, there was no flight found as you requested for.

USER: OK, no issues. Thanks for your response.

ASSISTANT: Thank you.