Budget reassignment not possible; budget spent and control param. not set

What causes this issue?

Budget has already been spent.

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?

If you still want to reassign values, you must make sure that the
following values are set in table <ZH>T77S0</>:
GRPID = HRECM
SEMID = BDGRA
GSVAL = 'X'.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.