Start a new print in that filament with it loaded in AMS slot 1. When it runs out, have AMS automatically switch to a new roll of the same filament in slot 2-4 to finish the print.
AMS has been a game changer for me on finishing up the ass ends of my filament that never got used.
P.S. - Am I the only one that told myself I’d get around to splicing that old filament but never did because I am too lazy?