Currently, WorkGuru will sync the current tax rate list in full from Xero. If you need to add, remove or update the tax rates, these need to be done in Xero and re-synced with WorkGuru. What you can manage in WorkGuru is the visibility of the tax rates synced from Xero. This allows you to ensure that incorrect or incompatible tax rates are not applied in WorkGuru.
From the accounting settings dashboard (Accounting -> Settings) click on the Manage Tax Rates link.
Select the required tax rates and click Toggle Active States to control their visabilty in WorkGuru.