You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I assist you?

USER:  Will you please assist me to change my existing reservation as my plan to meet my friend got postponed?

ASSISTANT: Sure, I am here to aid you.

USER: Thank you.

ASSISTANT: Ok, May I know your name?

USER: Elizabeth Davis here.

ASSISTANT: Ok, please wait for a moment.

USER: Ok.

ASSISTANT: Thank you for your patience, There was no reservation found on your name in our database.

USER: No issue. Thank you.

ASSISTANT: Thank you for opting us.