If you had not previously used lot numbers, and you have on hand balances of items that you now want to track, follow this procedure.
- Use inventory adjustments to bring the balance of the item to zero.
- Set the item as Lot Numbered or Serialized
- Receive the items to bring items back to the correct balance.
The above procedure will perform a journal entry for the 2 receipts but they will net to zero as long as the cost of the item does not change before doing the second receipt.