Unable to Enter misc issues transaction

Hi All, The business maintains items with lot control. When I check a particular items say ABC001 maintained without lot number. There are 10 quantities available without lot number. User realised and changed the master items, inventory tab, lot control option as 'Full control' from 'no control'. Here I must mention one point. Actually we cannot change the lot control options when there is a stock available in inventory. My understanding is that to change the lot control option at master item level first we must ensure that there is no stock available in inventory. But how they could change the lot control option, I am not getting any clue. Now the issue is we have to raise a misc issue transaction for 10 quantities of ABC001. and then we have to enable lot control option to 'full control' and have to raise a misc receipt with lot numbers. Now I am either unable to raise misc issue and/or not able change lot control option at master items. Kindly help me on urgent basis. Thanks in advance. JPReddy.