Add or remove iCloud Shared Photo Library participants in Photos on Mac
If you’re the organizer of a Shared Library, you can add and remove participants.
Add participants to a Shared Library
In the Photos app
on your Mac, choose Photos > Settings, then click Shared Library. Click Add Participants.
Type the name of a family member or friend with an Apple ID, click the name to select it, then click Add.
You can repeat this step to invite up to five family members or friends.
People you invite (or reinvite) receive an email asking them to join the Shared Library.
To send another invitation later, click the More button 
next to the person you want to invite, then choose Resend Invitation.
Remove participants from a Shared Library
When you remove a participant from your Shared Library, they receive a notification and can copy all of the items in the Shared Library to their Personal Library. A participant can’t remove other participants.
Note: If a participant has been part of the Shared Library for less than 7 days, they can only retrieve the items they contributed.
In the Photos app
on your Mac, choose Photos > Settings, then click Shared Library. Click the More button
next to the person you want to remove, then choose Remove.Click Remove from Shared Library.
If you later want someone to rejoin the Shared Library, you need to invite them again.