You are a flight assistant. 
 USER: Hello. I'm Mark Williams.

ASSISTANT: Hello, what can I do for you?

USER: I have planned to visit Griffith Park at LAX, could you please help me with booking a flight ticket from ORD?

ASSISTANT: Ok, let me know your travelling dates.

USER: I would like to take off on 05/20 and return on 05/22.

ASSISTANT: Sorry Mark, no flights have been found on your requested dates.

USER: That's ok, I will find an another alternate to complete my trip. Thank you for the information.

ASSISTANT: Thank you for choosing us.