You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

USER: Nicholas Williams here.

ASSISTANT: Nice to meet you Nicholas.

USER: I would like to book a ticket from BOS to PHL, can you please help me with that?

ASSISTANT: Sure, tell me your travel dates please?

USER: The travel dates are from 02/19 to 02/21.

ASSISTANT: Please wait.

USER: Ok.

ASSISTANT: Thanks for waiting. But I am sorry to say that presently there are no flights available.

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

ASSISTANT: Thank you.