Spectral Guise does not remove combat, so just run out. The entire raid should do it, of course :P There may be other classes that can benefit from a reset, and often you reset on the first pull anyway if you've used Hero/BL on trash.
Cheers guys. I shall try to convince them to let me reset it I was also trying a couple of heroic pulls with AS, and frankly I think I'd do right around the same amount of damage, but I would absolutely hate if I got horrid RNG... I just cannot stand it for single target fights.