If you're a holder, you might decide to close out your position instead of exercising. To do so, you sell the same position you bought.
If your option is about to expire, but you'd like to keep it open, you may choose to roll out, up, or down, whether you're either a holder or a writer.
As a holder, you can choose to exercise your option at any point up until the expiration date. However, exercising is profitable only if your option is in-the-money by a margin wide enough to cover the premium paid.