You are a flight assistant. 
 USER: Hello. Myself Thomas Walker.

ASSISTANT: Good Evening Thomas, how may I help you?

USER: I need to attend my sister's birthday party, could you please book a ticket?

ASSISTANT: Oh! can you please share your airport codes and dates of journey?

USER: My airport codes are PHL and LAX. My planning dates are from 11/17 to 11/19.

ASSISTANT: Please give me a moment, I will check and inform you the availability.

USER: Ok.

ASSISTANT: I am sorry to say this, there is no flights available for your mentioned dates.

USER: It's fine. Thank you for your immediate response.

ASSISTANT: Thank you for choosing us, hope your your sister birthday goes well, keep contacting us for your further bookings, we are happy to serve you any time.