Once again, the "collar turn"..........

so, the next step is to remove the stitches that are holding the collar to the collar-stand. Use care as the stitches are on the inside of the seam, ie. where the collar was sewed onto the stand is turned inside. (I apologize for the blurry photo.)

If your fabric is a bit thin (as mine was due to the age of the garment or in case of thin original fabric of the garment) there may be some damage done so, again, use a lot of care separating the collar from the stand, too.