You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

USER: I am Larry Johnson.  I want to change my flight reservation because I am unwell, can you please help me?

ASSISTANT: Sure, I will help you to change your reservation.

USER: Thank you.

ASSISTANT: Please give me a moment.

USER: Sure.

ASSISTANT: Sorry, no reservation found on your name to change your reservation.

USER: Not an issue, thank you for checking.

ASSISTANT: Welcome, have a nice day. Thank you for choosing us.