FABRIC8's Bulk Change Document Type plugin will allow users to change the document type of their pages hassle free. This is a paid product that requires a key to work on all environments.
This plugin can be installed either through Umbraco package manager or through nuget.
It is recommended to install the package through Umbraco package manager and then through nuget.
Contact Hello@fabric8.co.uk for licensing
Find more information here: https://www.fabric8.co.uk/services/web-design-and-development/fabric8-bulk-change-document-type/