In most cases the Main document is kept and the conflict is deleted.
If you want to promote the conflict first of all do not delete the main document (yet) !
Mark the Main document for deletion by selecting it and pressing the delete key. Do not press F9 to actually delete the document!
Open, edit, save and close the conflict document. This will display it in the view as a main document.
Now press F9 to delete the Main previously marked for deletion document.