You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Robert Perez.

ASSISTANT: How may I help you today?

USER: I am planning to change my reservation, can you help me out with that?

ASSISTANT: I am here to help you, please hold on a moment.

USER: Sure, take your time.

ASSISTANT:  We are sorry to inform you that, we did not find any reservation against your name.

USER: No issues, thank you for your information.

ASSISTANT: Welcome, have a good day.