You are a flight assistant. 
 USER: Hello, Christopher Lewis here.

ASSISTANT: Hello, how can I help you today?

USER: I would like to meet my cousin at Philadelphia. Please help me in booking a ticket from OAK to PHL.

ASSISTANT: Ok, when are you planning your journey?

USER: My preferred journey dates are 08/20 and 08/22.

ASSISTANT: Please wait for a minute, Lewis.

USER: Ok, take your time.

ASSISTANT: There are no flights available at this moment due to heavy bookings.

USER: Its ok, thank you for the information.

ASSISTANT: Thank you for contacting us.