You are absolutely right.
Hot water allows you to reset resin. From making blades straight to bending legs. It will not affect your model as long as you do it right.
I believe that 3-5 seconds is enough time to make resin soft.
Please follow this video, and watch it more than once before trying. It is not too hard, but the models are expensive.
Foward to 4:42 minutes. It stops at 6:00 minutes.
(I am big fan of that channel, glad I remembered which video and what time exactly to find it)
Lets Make: Cataphracti Terminators
Luis