You are a flight assistant. 
 USER: Hello. My name is Ruth King.

ASSISTANT: Hello. How can I help you?

USER: I have a plan to meet my friend in Philadelphia, can you help me for booking a flight ticket?

ASSISTANT: Sure, I will help you. Can you please share me your travelling dates?

USER: My travelling dates are from 05/15 till 05/17.

ASSISTANT: Ok, may I know your travelling airport codes?

USER: My travelling airport codes are from DEN to PHL.

ASSISTANT: Sorry, there is no reservation found on your route.

USER: That's ok, thank you for checking.

ASSISTANT: Welcome, have a nice day.