Development Magento Extension Bulk replacement of coupons"

Development of a customized Magento Extension „Bulk edit orders to replace the existing coupon codes by another coupon code” This extension should be able to bulk edit orders to replace the existing coupon code with 40 Euro discount (example) by another coupon code with 20 Euro discount. For example, I have 10 orders and I would like to select 5 of them at the same time and replace all existing coupon codes (40 Euro discount) by one specific coupon code (20 Euro discount) at the same time. A new order number should not be generated after replacement of the new coupon code and the date of the original order should not be changed by the date of the replacing the new coupon code as well. After replacement of the coupon code the invoicing respectively the calculation of the invoice amount should be consider only the new coupon code with 20 Euro discount. Add two columns at the order grid with filtering function, showing the quantity and SKU of the ordered items. This extension should not have an impact on other working extension. The extension should be tested and checked on a Magento test system first, before installing it on the live system. If you have any questions please feel free to contact me. Thank you.