If you say if you want to change the nature of trust (from negative to neutral or positive) it simply means that your old feedback is not valid.
Better to delete the feedback and write the new one.
Of course, some of these feedbacks aren't valid. Just retaliations. Even the OP has rightly admitted that. He isn't the only one who has done that.
The one that gets me really worried is this -
What happens when a member dies after leaving a red trust and the issue is later resolved?Anyone knows?