You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you today?

USER: I am Catherine Lewis. I want to change my existing reservation due to health issues, can you help me in changing reservation?

ASSISTANT: Please wait for a while, let me check your reservation and revert to you.

USER: Sure.

ASSISTANT: There is no reservation found with your given name in our data.

USER: No problem, thank you.

ASSISTANT: Thank you for approaching us.