Edit Targets Attached to Scan

Is there a way to edit a target after it’s been attached to a scan? The target list and exclusion list are grayed out are not editable.

No you can’t. If a target is used in a task you can’t change it anymore to ensure reproducible scan reports for every run of a task. You can circumvent that by creating an alterable task. As far as I remember you can change the target of an alterable task and therefore - if your target isn’t assigned to a task anymore - can change the target again.