The format providers of RadRichTextBox have the ability to convert different file formats from and to RadDocument. There is a list of the available format providers and illustrations of their use in this article.
However, the main focus of the format providers is not the conversion of one file type to another, but to aid the persistence of RadDocuments. There are also limitations when it comes to multi threading and thread apartment states.
Could you share some more details on the way you would like to convert the files, so that we can get the bigger picture and consider your scenario for possible enhancements to RadRichTextBox and RadControls as a whole?
Looking forward to your reply.
the Telerik team