Tell your sister she can back feed the power panel with a double plug extension cord. Be sure to open all the breakers first, especially the main. Wired generators should have an interlock between the gen and the main to avoid back feeding the distribution transformer and possibility killing a lineman.
With the main open, she will only power one of the two phases in her split phase panel; so, she should look for an outlet which is fed from the side of the panel she wishes to reverse power. T
