I have a Jira Project that was created before I joined the company that was meant to be used to track OKRs. To that end, the user who created it created an 'Objective' issue type and a 'Key Result' issue type. I believe the thinking was that the KR would always be under an Objective, so they made it a Sub-task type. Someone else then came along and created a 'Sub-Key Result' issue type, but as a standard level issue type. This has made it unnecessarily confusing and also essentially impossible to use these in Advanced Roadmaps properly.
What's the easiest way I can convert 'Key Result' into a standard level issue type, while still maintaining any 'child of' linking?