If you've marked your invoice as paid on Bonsai, it's easy to undo.

Just navigate to Financial Management > Invoices > select the specific invoice you'd like to update.

From here you can select the 3 dots in the top righthand corner of the invoice > select 'Undo Record Payment':

This feature can be beneficial in the event of any errors, if a check payment made outside of Bonsai fails to clear, etc.

By doing this, you revert your invoice to a "Outstanding" status. With that, any attached expenses will revert to an editable expense view under Financial Management > Expenses:

Once you have successfully selected "Undo Record Payment" (and your invoice status has been updated to "Outstanding"), you can edit the invoice details, if needed:

Please note: actioning an "Undo Record Payment" will not notify your client, with that in mind, you are responsible for any required communications to your client.

Once your payment has been successfully settled, you can mark your invoice as paid once again.