...And then the prayer does something more. It tells us that some things can be changed-" Tshuvah, tfillah, and tzdakah help the hardship of the decree pass" (line 21). We can be kinder, more forgiving, more generous. We may not be able to make our lives longer, but we can make them better, less bitter, more loving. We may find ourselves facing unintended circumstances, confronting situations not of our making. Those circumstances aren't inherently meaningful, but we can make them meaningful; we can give them purpose.
Hoffman, Lawrence A., Ph.D.. Who by Fire, Who by Water: Un'taneh Tokef (Prayers of Awe) (p. 214).