If the shocks are of the same stock length, then replaceing them one side at a time is the easiest way. Doing it one side at a time helps to hold the suspension height in check and help in removing and installing the shock. If they are lowered shocks you will have to remove both shocks completely. First you need to support or place a jack under the rear of the engine, high enough to take the weight off the rear wheel. It is best to have a buddy or two around then because when you go take off the shocks, you will need someone to support the weight of the swingarm as it will be free to drop to the ground with the shocks removed. The same person will be needed to help raise the swingarm to help align the shocks to their mounts. *Do not remove both shocks without supporting the weight of the bike from underneath or from the top with some type of hoist* A little Antisieze on the bolt threads wouldn't hurt either. Bigern
PS> Lifting the bike can be tricky, take your time to find it's best balance point. You need only to lift the rear enough to take the weight off the suspension. Leaving the kickstand down and letting the bike lean over on it helps stabilize the bike.