Change All Item

 Hi,
    I already implement Oracle OM,Inventory, Purchasing in our company. And now i am in the middle of implement Manufacturing. Now I have new business requirement that our customer need to change all the item that i have set earlier. What do i have to concern?
   
  For example: Item: 1102
                         Item Name: Coke
                       Change to Item 7001
                        Item Name : Coke

Now i have approximately 1500 item and the customer want to change all.

Please kindly advise, I need your suggestion before decide to change all item as customer requested.



Best Regards,

Poy