I can show you how to edit the Tax name and Description of the VAT rates.
You'll want to go to the Taxes menu, then head over to the section where you can edit the whole VAT settings. Here's how:
Go to Taxes.
Click the Edit tax button, then select Edit rates.
Hit the Edit link under ACTION.
Enter the new Name and the Description for the VAT rate.
Once done, hit Save.
Just in case you're wondering, the Tax Name appears on your transaction. The one that shows up on the Taxes page is the agency's name (which is reflected on the Agency Return form). If you want to edit the tax agency name, simply click the Edit tax button again then hit Edit settings.