'Necrons' that fail their WBB are removed from the table unless there is a Monolith to bring them through that turn. If they are not brought through a Monolith during that turn's movement phase then they are removed from the table.
Models that are removed from the table do NOT roll WBB, and therefore can not re-roll WBB.
Hope that helps.
Models that are removed from the table do NOT roll WBB, and therefore can not re-roll WBB.
Hope that helps.