Note: You can only remove yourself from a shared Vault if you were not the person who created the Vault.
To remove yourself from someone else's shared Vault
Open Elevault and open the menu (the three blue lines in the top left corner)
Tap Vaults Shared with Me
Tap the Vault you would like to remove yourself from
Tap Shared With
Tap Leave Vault
To remove someone from your shared Vault
Open Elevault and tap the shared Vault you would like to remove someone from.
Tap Modify Sharing.
Swipe a user's name to delete that one Connection.
Or tap Remove All to remove all Connections in bulk.