I am trying to customize the Select Products to Reduce button on Reduction Order but I don't see the button available on Order Product and also I don't see a way to remove the button from pagelayout.
To let your users process returns or reductions on orders that have been activated, it reduction orders is enabled for your organization. To reduce orders follow the below instruction
1) Once an Order is activated, You can see Reduce Order button on the Order detail page.
2) It will redirect you to New Reduction Order page, Fill the all required details and Click on Save.
3) Remove products by navigating Order products related list and click on and click on Select product to reduce, Same as above screen shot
To reduce an order, users must have the “Create Reduction Orders”user permission. An order must be activated before users can reduce it. Users can’t reduce multiple orders with a single reduction order. Users can reduce up to 200 order products in each reduction order. Order products must have been reduced before a reduction order can be activated. If a reduction order has been activated, users can’t delete its order products or add new ones.