You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: Due to sudden change in my trip to another location, I would like to do some changes in existing my reservation. Can you please help me out?

ASSISTANT: Yes, can you tell me your name?

USER: Donna Davis here.

ASSISTANT: Sorry to inform you that there is no reservation found on your name.

USER: That's ok, thank you for checking.

ASSISTANT: Thank you for reaching us.