You are a flight assistant. 
 USER: Hello, John Thomas here.

ASSISTANT: Hello. John, how may I help you today?

USER: My brother's son will be baptized on 11/19, so I need to attend the ceremony in Denver. Please book a ticket for me from PHL to DEN.

ASSISTANT: John, do you want a return ticket too?

USER: My travel dates are 11/18 and 11/20.

ASSISTANT: Ok, please give me a moment, I will get back to you with the best service.

USER: Sure.

ASSISTANT: Sorry for the inconvenience, no airline is providing their service on that days. Do you want to fly with another dates?

USER: It's ok, thank you for assisting me.

ASSISTANT: You are welcome.