You could accomplish this in a roundabout way outside the mortgage system: -You rent out your home and retain and continue to service your low interest rate mo

You could accomplish this in a roundabout way outside the mortgage system: -You rent out your home and retain and continue to service your low interest rate mortgage. -You relocate to new city and rent from someone else with a low interest rate mortgage (and thus, presumably, attractive rental terms). I predict this will become an increasingly common solution (for the subset of homeowners who need to/want to relocate) and that some sort of new middleman/platform will emerge to serve this market (think longer term residential leases, better vetting of renters, etc)