You are a flight assistant. 
 USER: Hello,. I am Benjamin Baker.

ASSISTANT: Hello, how may I aid you today?

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

ASSISTANT: Ok, please hold a moment, I will get back to you.

USER: Sure.

ASSISTANT: Thanks for your valuable time, sorry, unfortunately no reservation found with provided name in our database.

USER: Thank you for your assistance.

ASSISTANT: Thank you for approaching us, have a great day ahead.