Rolling over is a routine operation. Say you hold a long position on 1 contract of X with expiry in December. At the expiry date, you simultaneously sell a offs

Rolling over is a routine operation. Say you hold a long position on 1 contract of X with expiry in December. At the expiry date, you simultaneously sell a offsetting contract of X (canceling out your long one), and simultaneously buy a new contract with expiry in March.