Demoting Domain Controller

I have recently been tasked to develop an integration plan for merging two separate network domains. I want to migrate the smaller domain into the larger domain. The smaller domain is running Exchange, SQL and other services on its PDC. I plannedon demoting it to a BDC, but was wondering if there is anyway I can demote it to a member server? Sorry, re-installing is not an option. Don’t spend too much time on this, you’ll either know or you won’t. 100 points to the best answer. Thanks