If you need to replace your toilet tank, then chances are that it's compatible with the rest of your toilet (including the bowl or seat). This is because toilets have very few moving parts and most manufacturers follow the same basic design.
This means that you can move a new tank onto an existing bowl without any trouble at all. There may be some cosmetic differences, but if everything else is working properly, then this should not pose a problem.
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One thing to consider, however, is that most tank replacement kits do not include the fill valve and flush valve seal. Because of this, you will need to reuse your existing fill valve (just remove it from the current tank and attach it to the new one) and potentially replace the flush valve seal on your new toilet tank.