Cristiano Ronaldo can go back on a promise he made to former club Manchester United by returning to England with rivals Manchester City.After three years with Juventus, Ronaldo is ready to move on in the pursuit of a new goal and had been strongly linked to Paris Saint-Germain, whose interest has now waned after their acquisition of Lionel Messi.Ronaldo is open to leaving Juventus / Marco Canoniero / Getty ImagesRonaldo's agent, Jorge Mendes, is now looking for an alternative home for the 36-year-old, and according to…