The only way is the military in terms of planning end execution of Planning, Special Operations and USMC back up while in the hands of FEMA/HS temporary government likely headed by POTUS at 0:00 hour on Inauguration Clock.
The ONLY way under the Constitution FOR the US is to audit the election and declare the true and correct winner of the election. This could take time but after which the Congress and/or state legislatures would ACCEPT the DULY APPOINTED ELECTORS.