First, go to the list you wish to remove someone from.
At the bottom of the list there should be a ‘Share’ button with a number next to it (which indicates the number of people who the list is shared with). Select this.
A new screen will appear detailing the collaborators of the list. Select ‘Edit’ in the top right-hand corner. This will then show you the ‘Shared With’ screen. Find the person on the list who you wish to remove. The check box next to their name should be ticked.
To remove them from the list, un-tick their checkbox. The tick should disappear.
Next, select ‘Save’ in the top right-hand corner of the ‘Shared with’ screen.