Is it possible to remove any information about some package?

I installed something from debian respositories (even not official ones) and this package has been heavly modified. I dont want Debian to take care about it anymore, i also have problems with dependencies, which Debian thinks it has to install programs, but since i modified this package i dont need this dependencies anymore.

I read all man dpkg, and i couldnt find any optiom that would remove ANY information about specific package without actually removing this package.

So, is there any way to just remove it from debian dpkg files without risking that apt-get or dpkg will remove it phisically (its folders and files) when i run it ?

P.S. setting it 'on hold' with --set-selections didnt help me, becouse it still has not-needed dependiecies

That information is inside the debian/ dir of the source, where you can change the dependencies inside debian/rules and debian/control. Both are text files which you edit.