You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Richard Nelson.

ASSISTANT: How may I help you at this moment?

USER: I have planned a trip to enjoy my holidays in Philadelphia, so can you please help me in flight ticket booking?

ASSISTANT: Sure, I am here to help you with that one. Can you please let me know your planned travel dates?

USER: Thank you for considering my request and I would like to departure on 08/06 and back on 08/08.

ASSISTANT: Ok Richard Nelson, do you have any idea about the airport codes of your desired locations? If yes, please provide that.

USER: Sure, I have some idea about my airport codes and they are from LAS to PHL.

ASSISTANT: Ok, please wait a minute. I will check the flight availability and let you know the flight details.

USER: Ok, take your own time. I can wait for your response.

ASSISTANT: Sorry to inform you, there is no flight available in this route on the dates you have provided.

USER: Ok, that's fine. I can prefer another source to reach my location. Thank you for your help.

ASSISTANT: You are welcome. Thank you for choosing our travel agency.

USER: Welcome.