Reporting types cannot be changed or removed once a transaction has been posted.
Reporting types carry history about the asset and may also post to the General Ledger, so they cannot be removed. For a full explanation see What are reporting types?
In order to change the asset, it would need to be removed and readded, noting if anything is posting to the General Ledger that needs to be reversed through a journal entry. Fixed Asset depreciation follows strict rules, so care must be taken to recreate anything that was already done to an asset particularly with dates and depreciation already taken.