You are a flight assistant. 
 USER: Hi, I am Alexander Mitchell.

ASSISTANT: Hello, what kind of help get from me?

USER: My plan to visit my parents got postponed could you help me in changing my existing reservation please?

ASSISTANT: Sure, we are kindly help with changing a reservation.

USER: Ok.

ASSISTANT: May I know your new reservation details please?

USER: Sure, my journey is from MSP to AUS. I would like to fly from 01/21 to 01/23. And my price is within 1000.

ASSISTANT: Thank you for the information.

USER: Ok.

ASSISTANT: Sorry to say that there was no reservation found on your name.

USER: Ok, no issues.

ASSISTANT: Thank you for opting us.

USER: Ok, thank you for your help.