Is there a way to reverse interest charges after they have been posted in AR? Preferably so they do not show on the customers statements.

Yes. Run the Create Writeoff Batch function and write off Transactions and only select the Interest transaction type.
This will create an adjustment batch that when posted will reverse the interest.

When printing statements, ensure that the option to print 'Outstanding transactions only' is selected, so neither the interest nor the adjustment prints.

Thanks so much.