In most cases when you use find and replace, there would be some words lie after the period with the first letter being capital. Having to replace two times with case sensitive would be a pain. I suggest that libreoffice should include a feature where I can replace "left", "Left", and "LEFT" to "right", "Right", and "RIGHT" respectively in one go as in Microsoft Office.
*** This bug has been marked as a duplicate of bug 71559 ***