If Seneca has not done anything since the conditional formatting she can undo what her last action was. This is done by either pressing control+Z or by clicking on the undo icon.
If other actions have been done, there are a few more steps that need to be taken in order to clear the formatting. They are:
1. Select the cell or cells whose formatting you want to delete.
2. Display the Home tab of the ribbon.
3. In the Editing group, click Clear | Clear Formats.