How do I adjust an asset if I already have a provision for depreciation account in the trial balance

YOu need to know the depreciation method of the asset, the cost of the asset, the salvage value of the asset and the useful life of the asset, has well as the number of years it has been depreciated.

The journal entry to record the depreciation is:
Debit Depreciation Expense for the amount of depreciation.
Credit Accumulated Depreciation for the amount of depreciation.