You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: My name is Margaret Roberts.

ASSISTANT: How can I help you at this moment?

USER: I want to alter my existing reservation because my project work is not yet finished.

ASSISTANT: Sure, I will help you with this.

USER: Thank you.

ASSISTANT: Margaret Roberts, there is no active reservation found under your name in our database.

USER: Ok, not an issue. Thank you for helping me.

ASSISTANT: Thank you for choosing us.