Reduce Person Q

[Yechezkiel]

Are the only changes from Reduce Person the ones listed in the spell (+2 dex -2 str +1 size to hit and ac)?

I used to think going from medium to small, for example, would give you the +4 to hide Gnomes and Halfings get.

[Jack Mann]

You're in the next size category down, so yes, you do get the bonus to hide, as well as the penalty to grapple checks and other size-related shenanigans.

[Yechezkiel]

Where can I find that?

Pieces of it are in the phb but I was looking for a list of everything that changes.

[Dhavaer]

The Monster Manual. I think it's in the combat section of the PHB as well, under 'Larger and smaller creatures in combat'.