How do I change the tax on my MA-1400A-100/600?

It's been ringing in at 8% (which is ridiculous), we need to change it to 6.75% (For tax 1) and keep 1% (for tax 2). I have the manual, the only thing in there about tax is the "Tax test," and our local register company wants to charge $15 to fax me a piece of paper...