You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello.

USER: I am Sarah Phillips.

ASSISTANT: How shall I serve you?

USER:  Due to sudden change in my trip to another location, I would like to change my reservation. Can you please help me out?

ASSISTANT: Hold on, I will revert you.

USER: Sure.

ASSISTANT: There was no reservation on your name to change.

USER: Ok, no issue.

ASSISTANT: Thank you for opting us.

USER: Thank you.