You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am William Perez.

ASSISTANT: How can I assist you at this moment?

USER: I want to book a ticket from EWR to IAD to attend seminar, can you help me in booking?

ASSISTANT: Sure, I will help you with this.

USER: Thank you.

ASSISTANT: Can you please provide your planned dates of journey to proceed further?

USER: I am departing on 12/28 and return on 12/30.

ASSISTANT: Wait a moment please.

USER: Sure, take your time.

ASSISTANT: William Perez, there are no flight services available on this route on your provided dates.

USER: Thank you for your information.

ASSISTANT: Thank you for utilising our service.