You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Brian Collins.

ASSISTANT: How can I help you at this moment?

USER: Can you help me to book a flight ticket from ORD to DFW?

ASSISTANT: Sure, can you please provide your travel dates?

USER: Ok, my trip date is on 05/16 and return date is 05/18.

ASSISTANT: Wait a moment please.

USER: Ok, I will wait.

ASSISTANT: Brian Collins, there are no flight services available on this route on your provided dates.

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

ASSISTANT: Thank you for contacting us.