Link between Change master and BOM

Hi ,

when we change the Bill of Material (CS02) , the changes are directly effected into MAST and STPO . for example , if one component is deleted from the bill of material , this material entry won't be available in STPO table .

In case we use the change master , the process is to create the change document and then change the BOM with the change document in CS02. If we change the BOM by this way , the deleted component still reside in the STPO table . Now , how the system differentiates the active components for the bill of materials,

Regards

Mani