You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: My name is Ronald Roberts, can you help me to book a flight ticket from CO - DEN to PHL?

ASSISTANT: Sure, please provide your travel dates.

USER: Ok, please book a ticket for the dates June 4th and 6th respectively.

ASSISTANT: Do you have any class preferences?

USER: NO. Yes, please book a connecting flight and the return timing should be afternoon.

ASSISTANT: Sorry, we couldn't found any flights for you.

USER: Ok, that is not a problem. Thank you for assisting me.

ASSISTANT: Thank you for reaching us.