Swap both wings
Step 1 / 9
x': Whole cube: turn 90°, front face goes down
Each edge holds both wings of the other one, not flipped.
The last two edges on the left and right of the top. The x' at the start brings them to the front. Here Uw2 and Rw2 are two layers.
Step 1 of 9: x'. Whole cube: turn 90°, front face goes down