Releveling refers to the lifting of a structure that has experienced differential settlement.  Structures can be releveled after they are underpinned.  In these cases, hydraulic or mechanical jacks are placed on top of the underpinning pier or pile before it is attached to the foundation.  The foundation is lifted and then held in place until the pier or pile is connected to it with a concrete cap.

Cosmetic releveling involves leaving the existing foundation in place.  The existing framing for the structure is unbolted from the foundation and lifted.  A cap is installed on top of the foundation and the framing is reattached.

Pressure grouting can also be used to relevel a structure and is usually used when concrete slab floors have settled.  Holes are drilled through the slab and grout is pumped beneath it, lifting the slab.