I still can't delete the parents

Question

That doesn't work I'm one of the children & It's my tree that I'm building, if I delete me then there is no tree

Answer 1

Then you need to delete the ancestors from the top down.  You can't delete someone in the middle of the tree.

One thing you might try (if your real parents are in the tree (like with a sibling) you can select yourself then click on the [Change or delete] button then the [Change parents] button will let you select your real parents.