Styles in Excel
Deviate from a style
If you have applied a style to a set of cells and you change a formatting element of one of those cells, then modifications to that particular element of the style will no longer be applied to the modified cell.
So after changing a font attribute (like Bold) of a cell, changing the font attributes of the style will update all cells, except the one you just modified:
Series of cells with one style, 1 cell deviates from that style.
You can restore the style to a deviating cell by selecting the cell and choosing the style from the style dropdown and clicking "No" on the subsequent question Excel 97 - 2003 will ask you (See below) . Note that Excel 2010 (and 2013 and 2007) never asks you this question and performs the same action as when you click "No" . See the previous page to find out what clicking Yes or no causes Excel to do.
Confirm to Excel how it must apply the style