How do we automatically cancel fulfilment sales orders with a long Scheduled Ship Date?

We have a scenario whereby a fulfillment sales order is created and when there is no on hand it pushes the Scheduled Ship Date out by approx 700 days. It looks to reserve the stock in SaaS but the sales order never gets fulfilled when on hand is eventually increased/stock is received in the warehouse. In fact the sales orders simply stay at 'Awaiting Shipping' and requires manually intervention to cancel and free up the reservation! Is there a seeded process that someone knows that we can run that simply cancels these sales orders automatically or can