An apparatus that is usable with a well includes a first portion and a second portion. The first portion includes a first plurality of segments, and the second portion includes a second plurality of segments. The apparatus is deployable in a tubing string that is installed in the well, and the second plurality of segments is adapted to engage the tubing string and exert a force on the first plurality of segments. The first plurality of segments is adapted to expand to form a seat in the tubing string to receive an untethered object in response to the force, and the second plurality of segments is adapted to be released from the first plurality of segments downhole in the well.