Diagnosis
You want to do a date shift.
When you do a date shift, the valid-from date for all effectivityperiods of all linked objects is re-calculated by the system.
This changes the sequence of effectivity periods on &V1& for BOM &V2&,item &V3&.

System Response
The system checks whether the BOM is still consistent. The BOM is notconsistent if, for example, the BOM has already been changed with achange number with the same valid-from date as the new valid-from dateyou define in your date shift.

Procedure
Since your date shift violates the consistency of the BOM named above,you cannot carry out the date shift.