You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I address you?

USER: Please change my existing reservation.

ASSISTANT: Sure, may I know your good name for further process?

USER: Thank you. My name is John Phillips.

ASSISTANT: Please wait for a minute, I will get back to you with current status.

USER: Sure.

ASSISTANT: There is a reservation found with your name in our data base, please provide your new journey details for booking process.

USER: Sure. My travelling dates are from 07/10 to 07/12. My airport codes are from Seattle, SEA to Oakland, OAK.

ASSISTANT: Thanks for providing your journey details, please wait for a minute.

USER: Sure.

ASSISTANT: We found a flight with ticket price 900, southwest airline and flight number 1015. Shall I proceed with booking?

USER: Do not proceed, I need a flight under the range of 200 only.

ASSISTANT: Ok, thanks for approaching us.

USER: Thank you.