Demo Units

We are using Discrete Manufacturing module to Manufacture some of the products.  We have below requirements, please suggest.

We have only fixed assets module.

a) Let's say the discrete job is to manufacture 10 quantity of the assembly.  After the completion 2 units may be used for demo purpose either in shop floor or the sale rep is travelling with them.

     How to remove those from inventory, because they are demo units and need to be depreciated. 

b)  If sales rep sold the demo unit to the customer then we need to able to convert that into inventory item and ship the item through sales order.