The duty allocation cannot be changed; see long text

What causes this issue?

You want to change the start date of a duty allocation or extend/shorten
a duty allocation. This is not possible because the duty allocation
periods to be extended or shortened still contain absences that have
been entered in 24-hour intervals.

System Response

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

How to fix this error?

Delete the absences in the affected duty allocation periods and create
them again. They are then created automatically as calendar days. After
you have done this, you can change the start date or end date of the
duty allocation.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.