You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

USER: I want to change my existing reservation, can you please help me in this intent?

ASSISTANT: Sure, can you please tell your name to check your details?

USER: Sure, myself Thomas Young here.

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

USER: Ok, no issues. Thank you for your service.

ASSISTANT: Thank you and have a nice day.