You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: My name is William Campbell. I am having sudden meeting in my office, can you please help me changing my reservation?

ASSISTANT: Sure, I will help you with this.

USER: Thank you.

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

USER: No problem, thank you for checking.

ASSISTANT: Thank you for utilising our service.