Stepping sideways

All werewolves have the ability to "reach" or "step sideways" into the Umbra. This ability comes intuitively once the First Change passes. Somehow, they begin to sense the world waiting on the other side of the mirror. Shifting between worlds becomes a skill like walking; it's something that they can just do.

Stepping
But the Gauntlet lies in the way, and a werewolf must push through it to step sideways. In most places, the player must make a Gnosis roll against the Gauntlet rating. If she succeeds, the character slips through to the other side. Failure means that she can't push through the webs in this location and needs to move and try again. If she tries to enter the Umbra in the same place, Weaver-spirits reinforce the Gauntlet and the difficulty increases by two for each further attempt. On a botch, the character may get trapped in the Pattern Web, appear in the midst of a spirit storm or simply vanish for a while, only to reappear hours later with no memory of the missing time. A pack may nominate a single "opener of the way" to lead the entire pack into the Umbra. Garou have found a way to make it easier to reach into and out of the Umbra. Reflective surfaces, polished silver, a quiet pool of water and especially mirrors make stepping sideways easier. Some say that these aids let a werewolf concentrate on his true self and see his spirit. Others believe that they are holes in the Gauntlet, which reflect images because what lies on the other side isn't visible on Earth. Regardless, a werewolf who has access to a reflective surface has several advantages when trying to step sideways. First, the difficulty of the roll drops by one. Second, her attempts do not alert Weaver-spirits, so if she fails, she may try again in the same place with no penalties. Also, if the player botches, the reflective surface breaks, tarnishes or becomes agitated and unusable, rather than leaving the character trapped between worlds or missing time. Experienced fomori have a habit of breaking mirrors so that their opponents cannot flee. A common superstition also holds that werewolves need mirrors to emerge from "wherever it is they come from," which is blatantly untrue.

Souces

 * Werewolf: The Apocalypse Revised