SAP Message AA190 - Dep.start date taken over

Diagnosis
You have chosen the function 'Takeover Dep.Start' This function hasbeen performed.

System Response
From the capitalization date, the system has determined thedepreciation start dates for ordinary and special depreciation, forinterest calculation and has determined the changeover year.
When you create, values will be adopted in these fields from thisfunction.
If you change, however, values will only be adopted in these fields ifthe depreciation start dates are initial? or if the changeover year isinitial.