You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: I want to change my reservation, can you help me with that?

ASSISTANT: Sure, I am here to help you with that, can I know your good name to proceed further?

USER: Anthony Perez here.

ASSISTANT: I found your reservation, may I know your trip dates?

USER: My travelling dates are from Apr 14-16.

ASSISTANT: To proceed further I need your source and destination codes.

USER: My source code is PHX and destination code is OAK.

ASSISTANT:  Do you have any class preference?

USER: No.

ASSISTANT: Are there any more preferences that you want to avail?

USER: I would be comfortable with single stop over.

ASSISTANT: I got a connecting flight-1024 in economy class. Shall I proceed?

USER: You can proceed with booking.

ASSISTANT: Ok, booking is done on Southwest airlines.

USER: Thank you for the help.

ASSISTANT: Thanks for choosing us.