To Move Wordpress Mu To Another Directory or Upper Directory

How can I move wordpress mu installation out of its original directory to another directory or to upper level of directory? I tried to do this once, but it broke the already installed wordpress mu.

Can any experienced wordpress mu user here gives me a detailed instruction of what to edit, to move, to protect, and to change settings in specific files and folder in order for the moving of wordpress mu installed directory to work correctly? Thanks...