You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello,. How may I assist you?

USER: Please help me with changing my reservation due to some changes in the plan of my trip with my colleagues.

ASSISTANT: Could you please provide your name?

USER: Anthony Hernandez here.

ASSISTANT: I regret, no reservation exist by name Anthony Hernandez.

USER: No problem, Thanks for the information.

ASSISTANT: Thank you.