Use Extend when the start is worth keeping and everything after one point can be remade. If the ending is already good and only one middle section is wrong, use Replace Section.
Use Replace Section when the start and ending are good, but one middle span needs new audio or lyrics. Do not use it to continue the song past its current ending.
Use Cover when the tune is worth keeping and the genre, arrangement, or vocal feel is not. Do not use it to swap in a named singer — that is a different tool.
Use Mashup when one track has the hook and another has the feel, and you want a new song that borrows from both. It does not stitch the two audio files together.
Use Create Persona when a completed Rao v1.0 or Rao v1.5 generated song has the vocal and style identity you want to keep. It stores a reusable template. It does not clone a real voice from a recording.
