Conversation so far:
what are the names of the three pedals on a piano
Modern pianos usually have three pedals, from left to right, the soft pedal, the sostenuto pedal, and the sustaining pedal.
what does the soft piano pedal do
This pedal softens the note and also modifies its tone quality.
what about the sostenuto piano pedal
Using the sostenuto pedal, a pianist can sustain selected notes, while other notes remain unaffected.

Question: what does the sustaining one do
Self-contained rewrite: what does the sustaining piano pedal do