You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, welcome to Global agency.

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

ASSISTANT: Sure, let me check our database. Sorry, no reservation found by your name.

USER: Myself Paul Mitchell.

ASSISTANT: Paul, thank you for contacting us.

USER: Thanks for your quick response.