Revoice Pro is described as 'audio plugin used for vocal tuning, time correction and ADR. Revoice tightens timing, pitch' and is an app in the Audio & Music category. There are five alternatives to Revoice Pro for a variety of platforms, including Windows, Mac, Android, iPhone and Android Tablet. The best alternative is Celemony Melodyne. It's not free, so if you're looking for a free alternative, you could try GSnap or Voloco. Other great apps like Revoice Pro are Auto-Tune (Paid) and NewTone (Paid).
With GSnap you can get an auto-tune effect. It can be used subtly to correct the pitch of a vocal, or, with more extreme settings, to create a robot-voice effect. It requires a monophonic input signal to operate.
Voloco is a real-time voice-processing app that combines automatic tuning and vocoding. You can pick a song from your library to sing or hum along to, and Voloco will automatically guess the key of the song and pitch correct your voice to that key.