we are trying to change our sku numbers by using csv import
Any solutions/workaround for do it?
Well... by default it won't be possible because the SKU is used as "Primary Key" to allow Magento to identify if the record is new or is an update.
If this change is a one-time-only action, maybe you can work against your database directly.
SKU number is the unique number for a product in Magento. So You cant change Sku number using CSV file. If you want to change SKU number manually you can change using admin panel.
Go to Catalog -> Manage products section
Edit Product and Change SKU by this way but you cant change SKU value using CSV.
You can Change/Update other attributes data of product by CSV file.