You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I serve you today?

USER: I am planning to book a flight from DCA to EWR, so please help me in booking a flight.

ASSISTANT: Sure, we are mirthful to assist you.

USER: Thank you.

ASSISTANT: Kindly share if you have any airline preference.

USER: I need a normal-cost airline.

ASSISTANT: Do you need a stopover in between your journey?

USER: Yes, I need it.

ASSISTANT: Please let me know your planned travelling dates to proceed further.

USER: My planned dates are on Apr 21st to 23rd.

ASSISTANT: Is there any other specifications?

USER: No.

ASSISTANT: Ok, please wait a moment.

USER: Sure.

ASSISTANT: Thank you for waiting. Sorry, there are no flights found matching your essential details.

USER: Ok, no issues.

ASSISTANT: May I know your name please?

USER: Sure, I am Susan Young.

ASSISTANT: Thank you for choosing us.

USER: Thank you for your services.