You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is Katherine Williams.

ASSISTANT: How may I help you, Williams?

USER: I would like to attend my friend's birthday party at Seattle, please help me in booking a ticket.

ASSISTANT: Sure, may I know your journey codes please?

USER: My airport codes are BOS and SEA.

ASSISTANT: When are you planning your journey, Williams?

USER: My planned dates are 10/03 and 10/05.

ASSISTANT: Please give me a minute.

USER: Sure.

ASSISTANT: Katherine, I found a flight with Spirit airlines available with price 100. Shall I book the ticket?

USER: Ok, please book my ticket.

ASSISTANT: Your ticket is confirmed and the flight number is 1009.

USER: Thank you for your help.

ASSISTANT: Thank you for choosing us.