That depends on the boot.
Contact the manufacturer for details.
Typically, to resole a boot, you need to be able to remove the outsole (the rubber part that hits the ground) without damaging the padding. Or you need to be able to remove the midsole padding as well, while still having a way to reattach the sole.
Xero Shoes boots are not made to be resoled since we don't use (or need) a midsole that wears out. Plus, our shoes and boots have a 5,000 mile sole warranty.