You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Charles Williams here.

ASSISTANT: How can I aid you for today?

USER: Suddenly my friends changed the trip plan.So I want to change my reservation. Can you please help me for that?

ASSISTANT: Sure, let me check with your reservation. Can you please provide me your current journey details?

USER: My airport codes are from AZ-PHX to CA-OAK. My departure date is 07/04 and return date is 07/06. Make sure my price limit is 1.

ASSISTANT: A flight by Spirit airlines is found for your reservation details, shall I book it?

USER: Please proceed for booking.

ASSISTANT: Flight 1003 is booked for you.

USER: Thank you for helping me.

ASSISTANT: Have a great day.