command line: unmount a smb network drive

We use Windows Server for my company network.

I do use Mac has client. When I mount a network drive, I use the following command line:

osascript -e ‘mount volume “smb://myusername:mypassword@fileserver/department/its”'

everything works fine. I am a user administrator for my network, this is the reason why I guess I am able to mount the network drive in this way and everything works fine.

But my question is: how do I unmount this network drive? What is the command line?

thank you so much