You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

USER: Virginia Young here.

ASSISTANT: Ok.

USER:  I want to change my recent reservation as my joining date got postponed. Can you help me in changing?

ASSISTANT: Sure, I will help you. Please, wait for a moment.

USER: Ok.

ASSISTANT: Thank you for waiting, I did not find any reservation on your name to change.

USER: That's ok. Thank you.

ASSISTANT: Thank you for availing us.