You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: I am Joseph Walker want to travel to EWR from DCA, can you please avail me a ticket?

ASSISTANT: Sure, can I know your travelling dates?

USER: I want to depart on Apr 30th and return on May 2nd.

ASSISTANT: Do you have any particular time for departing and returning?

USER: Yes, I want to return in the evening.

ASSISTANT: Would you like to prefer direct flight or connecting flight?

USER: I prefer to travel in connecting flight.

ASSISTANT: Which class do you prefer?

USER: I am comfortable with any class.

ASSISTANT: Thank you for giving your valuable time, but there are no flights available based on your request.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for opting us, we hope to serve you again with better features.