It is possible you may be able to leverage existing dissertation work to complete a doctoral capstone.  Much of your research in the literature of your discipline will still be applicable, as will your exploration of real-world problems and issues which you undertook in planning for your action research dissertation.  Any networking you have done within your site may also be leveraged.

You will need to work closely with your faculty mentor to determine how to leverage your existing work toward completion of a doctoral capstone.  In some cases, depending on your progress, your faculty mentor may recommend you continue working on your dissertation.