A reset is intentionally stopping a combo before the end to do a mixup and catch the opponent unawares. This is usually a gamble to increase damage output; if the opponent gets hit by the reset then the overall damage dealt would be higher than just finishing the first combo.
Example
- Normal combo: Potemkin does a combo 5P > c.S > 5H > Hammerfall
- Reset: Potemkin does 5P > c.S > 5H > Hammerfall break, Potemkin Buster
This assumes the opponent is holding back or down-back during the combo and not jump or mashing a fast attack.