Merging Custom DocType

I have created several custom doctypes.

Several of these are masters, which should not have duplicates, unfortunately a couple of duplicates were created.

Is it possible to create a custom doctype, which can be merged with another? Along the same lines as an account or a project can be merged?

Never mind, figured it out.

Go to Doctype -> Form Settings -> Allow Rename

Once this is checked, two documents can be merged!