Our awning has some holes on each of the arms with little buttons to move either side up or down to slant the awning to let moisture run off. Totally manual, but doable. I am surprised that the rain ruined the arm, but I guess these things happen. You need to get with your dealer and get it fixed, probably under warranty.
2012 GMC 2500HD D/A Crewcab
2012 Jayco Eagle SuperLite HT 26.5 RLS
2009 Crestliner Superhawk 1900
2013 Polaris Sportsman 550 EXP
2008 Polaris Sportsman 700 X2