it seems from your question about the command in context, you are working with shell elements / working with surfaces in workbench .
a. if this is the case, and you have access to ANSYS Designmodeler , you can use TOOLS-> SURFACE FLIP, to reverse the area normals. ( easily done )
b. if you don't have access to Designmodeler, probably i suppose you need to insert command snippet in model tree, and use APDL commands to do so ( though i have not checked using this command in workbench, as have access to DM )
I was able to fix the problem by suppressing the multiZone meshing method in the mesh tree. I will try using the SURFACE FLIP with the multiZone unsuppressed in the future.