You can remove access to your company dashboard for people by removing them from your connections. Once you remove a user from your connection list, they no longer have access to your company. If you want to give them access again, you will need to send them a new invitation.
How to delete a user:
Navigate to settings > connections
Find the user you want to remove (scroll the list or search with name or email)
Click on the 3 dots next to the user on the right-hand side
Click Remove Access
Confirm your selection by clicking "Remove access" on the pop-up window.
You can also change the role of a user if needed. Read more here.