Standard&Poor's Ratings Services has affirmed its 'A' rating on Atlanta, Ga.'s water and sewer revenue bonds. The city is planning on allowing the letter of credit related to the series 2008 bonds to expire. Wells Fargo Bank has agreed to make a direct purchase of those bonds under a new Continuing Covenants Agreement (CCA). In order for this to occur, the bond ordinance must be amended to allow for the bonds to be converted to an "Index Rate Mode". Under this new mode, the bank will hold the bonds for a three-year period. At the end of this period, the bonds will be subject to a mandatory tender and may be extended or converted to another mode. Upon