Assignment cannot be changed for all work items

What causes this issue?

You want to make changes to work items of a selected job. However, there
are work items assigned to that job referring to a capacity split of an
operation. For these work items the assignment cannot be changed in the
job list.

System Response

The system removes work items that refer to a capacity split from the
list of changeable work items.

How to fix this error?

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.