Modifying Billable/Non-billable Time After Timesheet Approvals

<p>Are there any recommendations/best practices for modifying time-types on timesheet entries after they've been fully approved, but before running billing, short of un-approving individual timesheets and asking the users to make the change?</p><p>I realize we can have the billing rule pass everything through, and then just de-select what we don't want to be billable, but to preserve the audit trail, it would be preferable to actually go back to the original timesheet and modify those time entries directly.A  However, if the only way to do that is for the users themselves to do it, it will take a lot of