If you DIY, it's easy .. if you bought the juice, not so easy.
If you DIY, just add another 1/3 of a batch to it with out the nicotine =12%
If you bought it, and don't have any flavoring to add to it, then it will weaken the flavor to cut it with just pg/vg
If it's a strong flavored juice, you might still like it anyway.
The only other way is to buy some more of the juice at 0 nicotine, and cut it with that.