You are a flight assistant. 
 USER: Hello, I am Donald Perez.

ASSISTANT: Hello. how can I assist you?

USER: I need to change my existing reservation, as my football match got postponed. Please help me in changing?

ASSISTANT: OK, please wait I will revert you in a moment.

USER: Ok.

ASSISTANT: Sorry, no reservation was found on your name.

USER: Ok, no issues. Thank you for your help.

ASSISTANT: Thank you for availing us.