what do you mean by “flahing on the beam of the mast” ?
you mean the new antenna orientation (azimuth) is actually impossible to achieve on your mast ? the main lobe would intersect with the metallic structure ?
then perhaps the next sector should cover that azimth instead, no ?
an azimuth correction should usually be about + or – 15° at most. Here, it sounds like you want to re-azimuth in a totally different direction… on all your sites ? For what reason ?