How do I return a Kindle eBook early--I don't find the action button that I formerly saw
Without seeing your account, it's hard to know what advice to give you, so I'm going to just say what should happen. You should be able to delete the title from your Kindle device at any time. And if you go to Manage My Kindle in your Amazon account, you should see the title listed there with that action button to the right. When you hit that button, there should be an option to check the title in early.
You also always have the option of just waiting for the due date to pass and it will return automatically.
If you don't see anything on your Manage My Kindle list, then your title has already been returned. Are you seeing the title listed without a button or nothing there at all?
I hope this helps - please reply if you're still having problems.