Depreciation of fixed assets is a bit fiddly, hence I recommend that you make a copy of your database and do this in the copy so you can test things out.
Once you get the copy of the database ready Go to the Financial module > setup > Fixed assets > Calendar and setup your calendar year
Next: Click Transactions, point to Fixed Assets, click Select Assets, and then click New Group.
Name the group, and then click OK.
Under Current Groups, click the newly created asset group, click to select the assets for which you want to reset the life, and then click OK.
Click Transactions, point to Fixed Assets, and then click Mass Change.
Select the newly created asset group ID, click the Book tab, select the book ID, select Reset Life, and then click Apply Changes.
In the following message, click OK:
Are you sure you want to apply changes to group (New_Group_Name)
Do all this in test and see how it goes. This link might help: www.crestwood.com/.../
