You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

USER: I am John Williams. I want to change my flight reservation as my father is unwell, can you please help me?

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Sorry, no reservation found by your name.

USER: Not an issue. Thank you for checking.

ASSISTANT: Thanks.