  Duality symmetric electromagnetic action a la Schwarz-Sen is shown to appear
naturally in a chain of equivalent actions which interchange equations of
motion with Bianchi identities. Full symmetry of the electromagnetic stress
tensor is exploited by generalizing this duality symmetric action to allow for
a space-time dependent mixing angle between electric and magnetic fields. The
rotated fields are shown to satisfy Maxwell-like equations which involve the
mixing angle as a parameter, and a generalized gauge invariance of the new
action is established.
