You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you for the day?

USER: I want to do some changes in my existing reservation. Can you help me for that?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: May, I know your good name?

USER: My name is Kimberly Nelson.

ASSISTANT: Can you help me with your airport code?

USER: My travelling airport codes are from IAD to PHX.

ASSISTANT: When you are willing to travel?

USER: My travelling dates are July 28 and July 30.

ASSISTANT: Do you have any class preference?

USER: Ensure it is in the economy class.

ASSISTANT: We found 1011 Southwest airlines with 2 connection with price 100. Shall I proceed with the booking?

USER: No, I need a flight with 1 connection for a normal-cost airlines.

ASSISTANT: Sorry, we found no flights with your specification.

USER: Thank you for the information.

ASSISTANT: Thank you for reaching us.