Navigate in the WeGive Dashboard to the All Supporters table.
Next Click the filter button, and implement an Impact Number filter, searching for and selecting the Impact Card from which you would like to remove supporters from.
Click set filters, and your table will now display all supporters who are tagged in that Impact Number. Feel free to add more filters to narrow down your selection of supporters even more. Once all your filters are applied, select the supporters you would like to remove, either by selecting individually, the entire page, or all results and click the button in the top right to remove those supporters from the Impact Number.
If the data in the confirmation looks right to you, click confirm, and your supporters will be immediately removed from your Impact Number.