You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: William Smith here.

ASSISTANT: How can I assist you at this moment?

USER: Due to inconvenience of my work, I want to change my reservation. Can you please help me for that?

ASSISTANT: Sure, I will help you with this. Please be on hold for a moment while I check your reservation status.

USER: Ok, I will wait.

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

USER: Anyway, thanks for the information.

ASSISTANT: Thank you for utilising our service.