You can turn list sharing off entirely or on a list by list basis. Presently, it is not possible to unshare lists from specific individuals.To unshare a list with all people that received it, view that list and tap the "gear" icon to see list settings. From the settings screen, scroll to the very bottom and you will see a button "Unshare List". Pressing this button will unshare the list from others. Those users that received the shared list will no longer bee able to update your list, however they will retain a private copy of that list in the last state it was in when unshared. In order to re-share lists with others, you will need to share the list with recipients via their email address again.
Shopper Support Team.