Hi Satya,
According to my knowledge, unfortunately you can´t do it directly and after making a parameter change for the future logs modifications.
You need to have that 'change documents' are enabled for the class object table.
Using transaction O1CL, select tables you need, select class types from menu. The Change Docs' flag is then visible.
Please see with carefully note 65124 and 943559 - FAQ: Frequently asked questions about the classifctn. system
Regards,
Xavier