You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I need to change my existing reservation due to some issues, can you help me in doing that?

ASSISTANT: Sure, may I know your name?

USER: I am Nicholas Garcia.

ASSISTANT: Please wait a minute.

USER: Sure, take your time.

ASSISTANT: Sorry, no reservation found on your name.

USER: Ok, no issues. Thank you for checking.

ASSISTANT: Thank you for availing us.