Change the Depreciation key

Hi Freinds,

The users had put the depreciation key as "0000" implying that no depreciation is to be calculated on a particular asset. Subsequently, by using the T Code ABMA, the Manual Depreciation was provided and posted after doing the depreciation run.

However, the users now want to change the Depreciation key to Straight Line Method corresponding to 5 years of useful life. But the system does not allow to change the Depreciation key, giving an error message which reads as - "Manual Depreciation not allowed with Depreciation Key ZSL3". How can we resolve this? Is it really not possible to change the depreciation key and do we have to reverse out the Manual Depreciation?

Your help will be highly appreciated.

Thanks in advance.

Regards