You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can 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: Sure, can you please provide me your name to check the reservation?

USER: My name is Mark Harris.

ASSISTANT: Sorry, there is no reservation with your given name.

USER: That's ok, not an issues. Thank you for the information.

ASSISTANT: Thank you for reaching us.