I always forget/struggle with abilities that do damage and reduce a similar amount of max hp. How exactly does that work?

I always forget/struggle with abilities that do damage and reduce a similar amount of max hp. How exactly does that work? Say the PC is at full health and max HP = 50, with 10 damage dealt. So is it now 30/40 HP, or 40/40 HP?40/40

— Dan Dillon 👥 (@Dan_Dillon_1) January 23, 2020

And in accordance with that, let’s say starting HP is 34/44, takes 10 damage, so now HP is 24/34, correct? Correct! (assuming that 10 damage also lowers hit point maximum)

— Dan Dillon 👥 (@Dan_Dillon_1) January 27, 2020