You can decompose the relation, means break the relation into sub-relation.
Suppose there is partial dependency in a relation. So the relation is in 1NF.
Now you have to decompose the relation into sub-relations & check the relation in in 2NF or not. If the sub-relation is in 2nf then you convert the relation to 2NF.
As far as I know this is how you can covert.