They have no need to. They can simply repudiate their debts, as numerous states have done in the 1840s, 1868, and 1870s.
Puerto Rico's problem is that it is neither fish nor fowl, neither a city which has a legal escape route through bankruptcy nor a state which has a sovereign escape route.
Puerto Rico's problem is that it is neither fish nor fowl, neither a city which has a legal escape route through bankruptcy nor a state which has a sovereign escape route.