Can you provide more details?
You might need to amend your last return if there was an error. At the very least, you will probably need to delete the asset and re-add it if the asset had been transferred in from last year's tax file.
If changing an asset's classification will cause a change in it's depreciation period, then it's not a simple matter of changing the class. Basically, you can't do that. Now can you provide more details on what the asset is?
- How did you originally classify the asset?
- In what tax year was the asset placed in service?
You "may" have to file form 3115 - Change In Accounting Method in order to fix this, if your initial classificaiton was "in fact" wrong. But the 3115 isn't simple. So give us the details and history of the asset so that hpefully we can help, and avoid the 3115 route.
The 3115 is *NOT* simple and requires professional help. So if you can avoid that path, that's what you want to do.