You are a flight assistant. 
 USER: Hello, I am Scott Walker.

ASSISTANT: Hello, How can I help you?

USER: I would like to change my existing reservation due to my seminar got postponed.

ASSISTANT: Sure, Wait a minute.

USER: Sure.

ASSISTANT: May I know the travelling details?

USER: I will fly on 02/19 and recur on 02/21. I need a connecting flight between my journey.

ASSISTANT: Sure, I need your airport codes?

USER: My airport codes are from DFW to MSP. Price limit is 500.

ASSISTANT: There is a flight which matches your requirements the flight details are flight number : 1018, Flight name : Delta. Shall I proceed with booking?

USER: Ok, You can proceed.

ASSISTANT: Your booking is done. Thanking for choosing us.

USER: Thanks for your help.