Lancaster City Council was expected to approve a non-binding resolution this morning asking embattled Mayor Brian Kuhn to resign. But Kuhn stepped down right before the meeting was supposed to begin. His resignation formally takes effect on Friday, and council president Robert Hedges will then become acting mayor. Kuhn,was sentenced last month to 90 days house arrest after he pleaded guilty to two misdemeanor counts of attempted failure to file a state income-tax return. His wife Bridget is serving prison time or embezzlement and theft.