You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I aid you?

USER: I am Samantha Johnson. Please assist me to change an existing reservation as my plan to meet my old friend got postpone due to heavy rains.

ASSISTANT: Sure, We are here to help you.

USER: Thank you.

ASSISTANT: Give me a minute.

USER: Sure.

ASSISTANT: Thank you for waiting, but I am sorry to say that, there is no active reservation found with your name in our database to change it.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for choosing us.