When we refer to G‑d's presence within our world, giving life to all things, then She is the Shechinah.
When we refer to G‑d's transcendence beyond this world, we call Him "The Holy One, blessed be He."
In our prayers, we take the role of the Shechinah petitioning the Holy One, blessed be He.
Our mitzvahs, study and prayer unite these two aspects of G‑d into a perfect whole. This is the meaning of the phrase, "On that day, G‑d will be One and His name will be One."