You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I aid you?

USER: Can you please help me in changing my existing reservation?

ASSISTANT: Sure, can you please let me know your name?

USER: Ryan Harris.

ASSISTANT: Sorry, there is no active reservation found under your name to change.

USER: Ok, no issues. Thank you.

ASSISTANT: Thank you for reaching us.