Suno resists key changes because it treats the whole song as one harmonic world. You have to announce the modulation like it's an event.
1. Bracket it as an event:
[Final chorus: KEY CHANGE, modulates up a whole step, triumphant lift, bigger energy]
'Key change' + 'up a whole step' + 'lift' — three signals, one instruction.
2. Prepare the runway. Put a build before it: [Pre-chorus: rising tension, building to a key change]. Modulations need a launchpad — a flat verse into a key change feels random; a building pre-chorus into one feels inevitable.
3. If it won't budge, do it in the DAW. Get Stems, take the final chorus stems, pitch-shift up 1-2 semitones. Clean, exact, total control. This is how the pros do it anyway.
4. The cheat: generate the final chorus as a separate generation with [same song, one whole step higher, triumphant] in the prompt, then splice it onto the original in a DAW. Two generations, one perfect lift.
5. Don't modulate more than once. One key change is a lift; two is a roller coaster nobody asked for.
Good luck! Hank founder of SonorixPG