5e is actually quite clear that the CASTING of the spell is what requires components. Using actions granted by the spell - including shifting the effects to a new target - only require whatever behaviors and actions the spell says they do.

Call lightning does not require verbal nor somatic components after the initial casting. It is used explicitly by Wild Shape as an example of an ongoing spell you can continue to use the action granted by, when Wild Shape also explicitly forbids casting of spells (and, when you later gain the ability to cast spells in Wild Shape, it goes out of its way to describe how wild-shaped Druids substitute animal motions and sounds for the usual components).

The only requirement to call down lightning on subsequent turns is that the spell still be active and that you use an action to do so. No V or S components required.

The same is true of shifting hex or hunter's mark to new targets: you just use the bonus action they require to perform the shift. You do not need to obviously cast anything, because you are not casting the spell. You are taking a bonus action the spell allows you to take.