Repaint rebuilds one time window of a track and leaves everything outside it untouched. Set start and end in seconds, describe the new music, and the section regenerates in context with total duration preserved: rework an intro, replace an instrumental break, restyle a passage, or swap a chorus. To change sung lyrics inside the window, start the prompt with an instruction such as "Repaint the selected section with new sung lyrics:", pass the full lyric sheet with the new section in place, and turn Thinking off.