Issue

GST Rate Change
Solution Version 4:  Go to Financial Management > Setup > Sales Tax > Details
Version 2.6 - 3.7:  Go to General Ledger > Setup > Sales Tax > Details

Choose the code(s) that is(are) used for the GST.

Insert a new line or go to the next available line, and set this new Tax Detail up the same as the old GST rate, except change the rate to 6% (14% for the HST in this example) and the Effective Date to July 1, 2006.  The system will automatically know when to use the appropriate tax rate based on the effective date.  Remember to update all of your GST related tax codes!

See attachment for further explanation and for handling credit memos.