If the lessor wants to increase the rent with effect from March 1, 2007 the announcement must be delivered to the lessee on November 30, 2006 at the latest. In the case it is delivered later, let´s say on January 10, 2007, the rent can´t be increased sooner than May 1, 2007 even if the date of March 1, 2007 is mentioned in the announcement.