You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello. Is there any help that you need from my side?

USER: I am Brian Garcia. Can you please reserve a flight ticket to Philadelphia to attend a conference?

ASSISTANT: Yes, please let me know your travelling details.

USER: My journey dates are, Aug 16th and 18th.

ASSISTANT: Please let me know your regional airport codes.

USER: My airport codes are, SEA to PHL.

ASSISTANT: Please let me know is there any other specifications.

USER: I need a  flight ticket in business class.

ASSISTANT: As per your intent, there is no business class flight obtained on your travel dates.

USER: Ok, no problem. Thank you.

ASSISTANT: You are most welcome and have a nice day.