It can be difficult to truly “start over” in a genealogical search. It’s often impractical to re-obtain copies of records one has already taken time and money to acquire.
What can be a better approach to is to make certain that one has adequate citations for all the records and sources one has used on an ancestor or ancestral family.
Then one can “start over” the way many math students are told to start over on math problems. They are not told to relearn and re-discover every mathematical fact they’ve encountered. Putting away the old analysis, the old “work,” and the old attempts and starting that over is a good approach–students who can’t find their mistake by reviewing their work often are stuck because they can’t see the error they’ve made in the work they’ve already done. Doing it again can be a way to find their mistake.
Put away conclusions you’ve already made. Put away the conclusions you’ve gotten from others and start again with the information you have.