Reset
From Discworld MUD Wiki
Some spells and rituals reset when you cast or perform them again. This means that the remaining time and/or power from the initial performance or casting is not taken into account. So, if a ritual has a duration of five minutes, and you perform it again after only one minute has passed, it will last five minutes from the second performance... giving you a total duration of six minutes, and wasting the four minutes that remained on the original performance.
Examples
See also
Contrast with stack.