If you are a bully, then you can change. Firstly, try and work out why you bully others.
Apologise to your former victim - Do it privately and don't be upset if they are still suspicious of you - they just need to get used to the 'new you'
Get a job or do voluntary work - people outside school won't know that you have been a bully and won't be put of by your reputation
Develop new interests - find out about local clubs and groups you could join
Talk to someone about the problem
Take positive steps to help yourself. Some adults who were bullies as children often end up with all sorts of problems - failed relationships, few friends, frequent job changes, even prison records.
Save yourself future grief by stopping bullying now.