Here are the steps if you need to reverse a register.
Go To G/L Registers
Go to the Register needed to be Reversed. Select the Reverse. Select Reverse Register.
Here is a screen shot of the original entries in the GL Register.
Here is a screen shot of the Reversing Journal entries to review and click reverse.
When you click reverse it will prompt you to verify you want to reverse the entries.
Once the entries are reversed it will create a reversal GL Register