Stephanie Blythe sings in Handel’s Rodelinda. Also featured is Shenyang as Garibaldo. GP at the Met: Rodelinda airs April 22 at 12 p.m. on PBS (check local listings). In New York, THIRTEEN will premiere the program Thursday, April 19 at 8:30 p.m. with an encore presentation Sunday, April 22 at 12:30 p.m.