Pavan,
Reset is not recommended in a live system. Reset would only delete Asset tables (Transactions and master data). The MM documents would still remain intact, and therefore it would create a mess for you.
Based on your query, it looks like only when 1 plant was missed when loading data. Why not just load it via AS91 as Ajay recommended. Pretend as if that plant never went live, and now load the balance (APC/Accl Dep) for the asset of that plant.
Thanks
Asheesh