If you are replacing a sprocket, you should replace both sprockets, and the chain. These work as a system and tend to wear together. That said the rear sprocket is easier to replace as it just unbolts from the rear wheel once you have the rear wheel removed.
The front sprocket will likely require impact tools, and is accessible under a cover. If you feel you need to take the chain off, there is a C-clip holding the master link in place. Locate and remove the C-clip and master link to remove the chain.
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If you are replacing a sprocket, you should replace both sprockets, and the chain. These work as a system and tend to wear together. That said the rear sprocket is easier to replace as it just unbolts from the rear wheel once you have the rear wheel removed.
The front sprocket will likely require impact tools, and is accessible under a cover. If you feel you need to take the chain off, there is a C-clip holding the master link in place. Locate and remove the C-clip and master link to remove the chain.