You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello,.

USER: I am Donna Thomas.

ASSISTANT: How may I assist you?

USER: I want to attend a seminar at Phoenix. Can you help me in booking from Dallas?

ASSISTANT: Ok. Please provide your journey dates?

USER: My journey dates are from 12/02 to 12/04.

ASSISTANT: Please let me know travelling codes?

USER: My airport codes are from DFW to PHX.

ASSISTANT: No flight found for your requirement.

USER: Ok, No problem.

ASSISTANT: Thanks.

USER: Thanks for the  information.