You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. how can I assist you today?

USER: I am William Perez have to attend a business conference, can you book a direct flight?

ASSISTANT: Sure, please mention your travelling dates .

USER: Sure, my travelling dates will be 05/18 and 05/20.

ASSISTANT: Please mention your airport codes that you want to travel.

USER: Sure, I want to travel from PHL to OAK.

ASSISTANT: Please give me a moment.

USER: Ok.

ASSISTANT: There is no flights found under your details.

USER: That's ok, thank you for the information.

ASSISTANT: Welcome, have a great day.