I changed the income account on a product and services item. how do i make this change to be retroactive to change the items already processed ?

Hello chris107, 

Thanks for connecting with us here again. I'll be glad to point you in the right direction so you can continue to focus on your business with peace of mind. 

The ability to edit transactions retroactively at once is unavailable in QuickBooks. You'll have to manually edit each of the transactions in order to get the desired outcome. I can see the benefit of having this feature and I encourage you to send feedback about this to our engineers. To do this, click on the Gear icon and look for Feedback. Product ideas and improvements are based on the valuable feedback we get from users like you. I also suggest looking into third-party apps that can help you with editing your transactions retroactively at once. You can search for these apps on our site www.apps.com. 

Let me know if this info helps. I'll be one message away in case you have other questions. Otherwise, I wish you a great rest of the week!