varying
v.v. changing something so that it is not always the same. You do this to make things more interesting or to fit different needs.
v. modifying or altering something to create diversity or to adapt to specific circumstances. Often used to describe the intentional adjustment of a pattern, pace, or quantity.
The chef is varying the menu to use seasonal vegetables.
By varying the intensity of your workout, you can improve your fitness faster than by doing the same routine every day.
The composer achieves a sense of dynamic tension by varying the tempo throughout the second movement, never allowing the listener to settle into a predictable rhythm.
The verb is transitive when it means to change something else, but can be intransitive when something changes on its own.