To turn off bold, italic, or underline, select the cells that contain the font style you want to remove and click the buttons (Bold, Italic, Underline) again on the Formatting toolbar.
You can remove the alignment you've added to a cell or range of cells by changing it back to the General alignment setting. To do so, select the cells that have the alignment you want to change, choose Format Cells, click the Alignment tab, and choose General in the Horizontal drop-down list.
Another way to remove the alignment you've attached to a cell or range is to use the Edit, Clear command and choose the Formats option from the Clear menu. Be sure to first select the cells that contain the formatting you want to clear. Then click the Format menu, choose Clear, and choose Formats. This action clears not only the alignment but also the fonts and other formatting you added to cells.