Basically there are 4 steps:
Rename old table
Create new table
with partitioning
Add constraint on old table for it's proposed partition ranges
Attach old table as a partition to new partition table
Sounds easy right?
What about indexes? What about Triggers?
And guess what, there are other traps to watch out for!
P. Aczel. Logic, Methodology and Philosophy of Science VII Proceedings of the Seventh International Congress of Logic, Methodology and Philosophy of Science, volume 114 of Studies in Logic and the Foundations of Mathematics, Elsevier, (1986)