You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Joseph Perez here.

ASSISTANT: How may I help you Joseph Perez?

USER: Suddenly, I have changed my plans. Can you change my recent reservation?

ASSISTANT: Sure, I will do it for you. There is reservation under your name.

USER: Ok.

ASSISTANT: What would you like to have a change in this?

USER: Yes. Can you change my source and destination location?

ASSISTANT: Yes, could you please provide me your source and destination?

USER: Now, I like to go from LAX to PHX.

ASSISTANT: Could you please provide your journey dates you would like to \travel?

USER: From 08/06 to 08/08.

ASSISTANT: Sorry, Joseph there is no flights on your preferable dates.

USER: It's ok. Thank you for checking.

ASSISTANT: It's my duty, thank you for contacting us.