When entering Opera for Windows, you will be presented with the System menu. Yours may look a little different as user rights to the menus can be configured within the software,
Click the VAT Processing menu option or press V on your keyboard.
VAT Processing is where all the VAT codes and their associated rates are held. There will be two rates to change, one for Sales and one for Purchases.
Click the Next menu option or press N on your keyboard.
You will now need to edit the standard VAT code for Purchases. Click the Edit menu option or press E on your keyboard.
Click on the Rate 1 % box. If you are entering the new rate on or after December 1st 2008, you can just edit the VAT Rate 1 to 15.00% but if you wish to enter the new rate prior to this date, you can utilise Rate 2 and enter the date in which the new rate becomes effective.
You must now save this change by pressing F9 on your keyboard.
Click the next menu option to change the VAT code for Sales.
Click next until you find the Sales Standard Rate.
Click on Edit.
As above, amend either the rate 1, or rate 2 box to 15.00%
You must now save this change by pressing F9 on your keyboard.
The two VAT rates have now been changed.
Click on the Quit menu option, or press Q on your keyboard.