Qalb can be subdivided into total reversal and partial rearrangement. In a total reversal, the whole consonantal sequence is inverted. In a partial case, only some letters exchange positions while others remain in place.
«اللهم استر عوراتنا وآمن روعاتنا»
O Allah, conceal our vulnerabilities and grant security against our fears.
«عوراتنا» and «روعاتنا» reorganize portions of the same consonantal material. This is better understood as partial reversal than as a simple difference of one sound. The paired petitions for concealment and safety are linked by sound and sense.