Change Dates in Scan document: Photoshop

There are 4 scan pages , want to change dates in scan document. 1)HGS: Change dates from Feb 29 2012 to new date **3rd September 2012** and from March 20th 2012 to **27th September 2012** 2) Indigo change : Top 6th July 2010 to **1st Feb 2010** and in paragraph change 6th July 2010 to **1st Feb 2010**. 3) Quasar change : Top Jun 23 2009 to **Jan 23 2010** and paragraph 23rd March 2009 to **23rd Jan 2010** 4) Siro change : Top December 11 ,2006 to **11 December 2005** and in paragraph **December 11 2005**