You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you at this moment?

USER: William Roberts here. Please book a ticket from SEA to LAX, for attending a function in my aunt's home.

ASSISTANT: Sure, can you please provide your planned dates of journey to find the flights availability?

USER: Thank you, my preferable dates are from 05/13 and 05/15.

ASSISTANT: Give me a moment please.

USER: Sure, get back with good airlines.

ASSISTANT: William Roberts, there are no flights available on this route due to heavy bookings.

USER: It's ok, thank you for your quick response.

ASSISTANT: Thank you for contacting us.