Codeko

With this plugin you can set any post type (or posts types) as parent of any post type.
Urls will be wellformed, redirects will work, breadcrumbs will work fine.
This plugin is recomended when you need a url structure with a mix of post types. Any url structure you can imagine could be done.
Post types rewrite slugs will be ignored

Custom Posts Parents

Set any post type (or types) as parent of any post type. Any post structure can be created with this plugin.

Dmitriy Amirov

Simple plug-in for editing the parent comments to any user comments. Use it to edit the threaded structure comments.

Change Comment Parent

First review

Simple plug-in for editing the parent comments to any user comments. Use it to edit the threaded structure comments.

Custom Posts Parents vs Change Comment Parent