import re
names = ['Johnson, Dr., PWE', 'Peterson, FDR', 'Gaber, Dr. GTZ']
for idx, item in enumerate(names):
names[idx] = re.sub(r'([^,\n]+,\s*)(Dr\.),?\s*', r'\2 \1', item)
print(names)
aW1wb3J0IHJlCm5hbWVzID0gWydKb2huc29uLCBEci4sIFBXRScsICdQZXRlcnNvbiwgRkRSJywgJ0dhYmVyLCBEci4gR1RaJ10KZm9yIGlkeCwgaXRlbSBpbiBlbnVtZXJhdGUobmFtZXMpOgogICAgbmFtZXNbaWR4XSA9IHJlLnN1YihyJyhbXixcbl0rLFxzKikoRHJcLiksP1xzKicsIHInXDIgXDEnLCBpdGVtKQpwcmludChuYW1lcyk=