Within RW Elephant, all Rental Orders start out as Proposals. When you create a new Order, the default Order Status will be "Proposal."
Proposals do require Off-the-Shelf and Restock times and they do check for Item availability. Once an Item is on a Proposal, it cannot be put on another simultaneous Order.
If the Customer wants to reserve the Items on their Proposal, they must take the necessary steps to Confirm the Order.
If the Customer does not want to reserve the Items on their Proposal, it must become canceled for the Items to be "released." A Proposal may become Canceled manually by a User or automatically on its Expiration Date (if you've chosen to automatically cancel your Proposals).