Replacing or Moving Elements

Replace Elements: Right-click the element to be replaced and select Replace... Select the replacing element and optionally, select Delete to delete the replaced element as well as its exclusive parents.
Replace a Body: Right-click the attached body and select Replace... Select the replacing body.
Change the Sketch Support: Select the Sketchx.object > Change Sketch Support command then the replacing plane or face.
See also Creating Replace Face Features, Reordering Features, and Reordering Sketch-Based Features.