To change the direction of cells in Excel 2007 from right to left to left to right, you can follow these steps:

1. Open Excel and click on the Office button in the top left corner.
2. Click on Excel Options at the bottom of the menu.
3. In the Excel Options window, click on Advanced in the left-hand pane.
4. Scroll down to the Display options for this workbook section.
5. Under the Default direction section, select Left-to-right from the drop-down menu.
6. Click OK to save the changes.

This should change the direction of the cells in your Excel workbook from right to left to left to right. If you have multiple workbooks open, you may need to repeat these steps for each workbook individually.