Now I get it. I can not delete it from the community but can change the content. Then the only problem is to find/make content for the post to that community. Then, copy and paste the original post into the right community.
I got stuck trying to delete the original post from the wrong community. So now I know how this work, always learning; you are alive as long as you learn :) Thanks for the info.
It was my pleasure to help.
PS.
the post can be deleted from the blockchain, actually -- before it will have at least a single upvote. 😎