This is not necessary in order to get correct star alignment. PixInsight's StarAlignment does align images before / after meridian flip correctly.
If you still want to rotate the first 46 subs (e.g. to facilitate comparing the subs in the Blink process), create an ImageContainer (right click on the PI desktop), add the files, set output directory and output template (e.g. &filename;_rot&extension; ). Then open the FastRotation process, choose Rotate 180° and drag the blue triangle of the ImageContainer onto the lower gray bar of the FastRotation process window.
Bernd