You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Margaret Hill here.

ASSISTANT: How can I assist you?

USER: I want to change my existing reservation, please help me out.

ASSISTANT: Sure Hill, please wait a moment.

USER: Ok, take your own time.

ASSISTANT: I found your reservation, can you please share the airport codes?

USER: my source code is PHX and destination is IAD and please make sure there will be 1 connection.

ASSISTANT: Sure, can I know the travel dates please?

USER: My desired travelling dates are 03/11 and 03/13.

ASSISTANT: Ok, wait a moment please. There is a flight in Hawaiian airline with price 100, can I proceed?

USER: Please confirm with my booking.

ASSISTANT: Your reservation has been changed with the flight number 1001.

USER: Thank you for your service.

ASSISTANT: Thank you for approaching us.