I attached my file, I want to flatten lower splited cone, please anyone has experience then please share your knowledge.

I use lofted boss/base command to create a cone and then make a shell of 0.1875in thick, If anyone can flatten this cone and knows how to convert that lofted boss/base to sheet metal and then convert to flatten please show me. I want to learn.

This design gives me an error while I was trying to so sheet metal lofted bend command. that's why I ended up with this normal lofted boss/base command and now it want allow me to flatten.