Paul LeBlanc, president and CEO of Southern New Hampshire University, said Wednesday he plans to step down in June after more than two decades in the role. LeBlanc is credited with transforming Southern New Hampshire from a small regional college with just a few thousand students to an online behemoth with over 160,000 students last fall. Lisa Marsh Ryerson, who has been Southern New Hampshire’s provost since last year, will step into the presidency for a two-year term beginning in July.