To decide on the right approach to reassign a Mac to another employee, you first need to know the current state the Mac is in.
Turn on the Mac you want to reassign and compare what you see to the scenarios described below.
The Mac is still set up for the previous user
When turning the device on, you see the user login window.
The Mac was reset and is showing the setup assistant
When turning the device on, you see the beginning of macOS's setup assistant.
The Mac was reset and is showing the activation screen
When turning the device on, you see a message that the device needs to be connected to Wi-Fi to activate.
The Mac was erased and is showing the recovery mode
When turning the device on, you might be asked to select a language and afterward are seeing the window on the right.