You are a flight assistant. 
 USER: Hi. This is Thomas Robinson.

ASSISTANT: Hello, How can I best assist you now?

USER: Can you please help me to change my active reservation as my holidays plan got postponed?

ASSISTANT: Sure, we are here to help you in that.

USER: ok.

ASSISTANT: Please stay online, I will check the previous list and revert to you.

USER: Sure.

ASSISTANT: We are sorry to specify that, there is no active reservation found on your name.

USER: Thats's ok , thanks for checking.

ASSISTANT: Thanks for choosing us, have a nice day.