We have been having trouble with Out of Stock acknowledgments going to Petco. We acknowledge them as detail & change and then change the quantity to 0. It will still show as an open order with Petco, what else should we be doing.
So the order will not automatically close after sending that acknowledgement as out of stock. If you do need to close that order I recommend manually closing the order.
You can manually close it by pulling up that order and in the top right there will be a few icons and one of those with the X in it, sorry bad description, and that will allow you to close the workflow and the order in your fulfillment.