Reserve Stock for a Work Order
ServiceVisit lets you set stock aside for a Work Order before the visit happens. You would use it when you already know which parts a technician will need, so nobody else uses them in the meantime.
You pick the item, the location it will come from and the quantity. The quantity must be greater than zero and no more than what is currently available at that location, meaning on hand minus what is already reserved. ServiceVisit raises the reserved figure, leaves the on-hand quantity alone, and writes a Reserve movement that points to the Work Order.
The Work Order's inventory page shows, for each item, how much was reserved, consumed and returned, and how much is still reserved. Using the parts on the job is a separate action, and so is releasing an unused reservation.