about merge NPM to SAM ( application and database)

My company have the NPM and SAM application in the environment. NPM and SAM have been independent deployed.

Now we need NPM merge to SAM now. but I have the problem about with the NPM database .

I backup NPM database and recovery + rename the database to SAM database server, but the NPM installation be auto accessed to SAM database, I can't assign NPM access to NPM database. So NPM hasn't got any info from NPM database.

I have try used 'configuration wizard' to change the database, but If change access to NPM database and SAM will be change access to NPM database ,too.

So how can I merge NPM to SAM ?