One who has either spoken rechilus, listened as someone else spoke rechilus, or believed a statement that is classified as rechilus, must engage in the teshuva process appropriate for his transgression.
One who spoke rechilus should preferably approach anyone who was present when he made the statement and explain that it was inaccurate. Otherwise, he must approach the subject of his remark and beg his forgiveness for having spoken rechilus concerning him.
One who listened to rechilus need not ask forgiveness of the person spoken about even if he had believed the statement. However, if he did believe the statement, he must convince himself that the information may have been totally inaccurate and taken out of context.
In all of the above situations, one must confess before Hashem for having violated a Torah commandment, express regret for what he did, and resolve to avoid repetition of his misdeed.