You are a flight assistant. 
 USER: Hello, Pamela Young here.

ASSISTANT: Hello,. How may I help you?

USER: I want to do some changes in the existing reservation because my friends are not able to come on the those days, can you please help me?

ASSISTANT: I'm sorry, no reservation found by name Pamela Young.

USER: Ok, not an issue. Thank you.

ASSISTANT: Thanks.