The below process is somewhat manual in the process, but it’s been validated a few hundred times by myself personally.
I like to think of VMware’s Virtual Hardware as a virtual motherboard, I remember this explanation was included in the VMware JumpStart materials I used to deliver back in the VI 3.x days. And the Virtual Hardware comes with certain capabilities and restrictions. Newer motherboards are capable of more processors, more memory, more efficient, etc. And commonly, what you normally need to add/remove or replace on a motherboard is the same as Virtual Hardware, in that it often requires a power down to replace or upgrade such items. Yes Hot-Add has changed this somewhat, and definitely for the better, but it’s sometimes an afterthought in many peoples VM templates.