Removing the Macrium Reflect recovery option from your system's boot menu is normally done by using the Reflect user interface itself. Try that first by selecting Other Tasks -> Add Recovery Boot Menu Option... in Reflect's top menu and then No Menu -> OK in the popup dialog as shown in the screenshot below. If that doesn't work, it may be that your system's boot configuration data (BCD) store has been corrupted somehow. It can be repaired by booting to your Reflect rescue media and running the "Fix Windows Boot Problems" utility option as explained in this KB article.