QUOTE (Muspellsheimr @ Apr 15 2010, 03:26 PM)

The act of rerolling the dice replaces the previous state with the new result. You reroll the dice that did not score a hit, and if the result of the reroll does not contain enough 1's to be a Glitch, the test does not Glitch - as there are no longer enough 1's to trigger the glitch.
Rerolling does not 'add new dice', it 'replaces the previous roll'. This is the definition of rerolling.
I have to disagree that the act of rerolling replaces the previous state...sort of. SR4A, page 62: "When Edge is spent on a test, any dice that roll sixes are counted as hits and then re-rolled. Thus dice rolled with Edge can potentially generate more than 1 hit (since you keep re-rolling sixes)." Now, this bit *does* include rules text that suggests that it is an exception, but it still stands as a clear example (in the Rules As Written) that not all re-rolls are, by definition, examples of rerolling.
Now, all that this really does is to point out why game designers need to be careful when using terms that have out-of-game definitions in rules text; at the very least, they should differentiate the terms in some way. Imagine, for example, the following alternative rules:
a) "Whenever you are instructed to Reroll dice, pick up all of the dice in question and roll them again. The original result is treated as though it never happened.
b) "When Edge is spent on a test, any dice that roll sixes are counted as hits and then re-rolled. Thus dice rolled with Edge can potentially generate more than 1 hit (since you keep re-rolling sixes)." (Rule of Six)
c) "You may Reroll all of the dice on a single test that did not score a hit"
This sort of wording would allow the designers to differentiate between times when the previous state of the dice matters (like when re-rolling the 6s in the Rule of Six) and times when the previous state isn't intended to matter.