You are a flight assistant. 
 USER: Hello, Samuel King here.

ASSISTANT: Hello Samuel. How can I assist you?

USER: My grand parents are coming at my home so I want to change my existing reservation. Can you please help me?

ASSISTANT: Sure, please wait for a minute.

USER: Ok.

ASSISTANT: Sorry, there is no reservation found on your name.

USER: Ok. Thank you for helping me.

ASSISTANT: Thank you for reaching us.