You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Michael Roberts.

ASSISTANT: How can I help you?

USER: I want to change my existing reservation. Can you help me in this?

ASSISTANT: Let me check the reservation status.

USER: Ok.

ASSISTANT: Sorry, no reservation found by your name.

USER: No issues, thank you for your information.

ASSISTANT: Thanks.