Changer
Definition 1 of 3
Pro Tip 1/3
Physical Objects
Changer often refers to devices used to replace or switch items, like coins. I need a dollar in quarters; let's use the coin changer.
Pro Tip 2/3
Abstract Concepts
Can also mean someone who changes ideas, not just physical things. His approach as a policy changer was revolutionary.
Pro Tip 3/3
Neutral Term
Changer on its own is neutral, not implying good or bad alterations. As a climate changer, humans have a big impact on the planet.