Opinion change
Opinion change is a feature of an campaign
Opinion change can occour when the target of the campaign or general perception of it changes. If a certain proportion of the campaigners call for a vote on opinion change such a vote will be arranged and as a result a "fierce" call for boycott can mellow down to a "slight avoid" or even morph into a endorsment. Opposite if of course possible.
Those campaigners dissatified with the opinion change are free to split or just change their stake to another campaign or form a new one.