Evans, who received immunity from prosecutors, was the first to admit forging a signature.
She also confessed that she had lied when she was first interviewed by federal authorities on Oct. 1, 2010.
"Most of the information was not true," Evans said, adding that she was trying to protect Brown, with whom she had worked for a decade.
When Evans was contacted again by investigators in April 2012, she said, she answered questions truthfully.
Evans told jurors that Brown had called her into her office in 2009 in the schools' administrative headquarters in Bala Cynwyd and showed the last page of a document. She said Brown told her she needed some names quickly for a contract between Planet Abacus Charter School and AcademicQuest L.L.C., one of Brown's management firms.
Evans said she suggested her aunt and her sister, Elizabeth Kennedy.
After Evans signed her aunt's name, she said, Joan Woods Chalker, who was the chief executive of Planet Abacus, signed Kennedy's name.
In April 2012, when the federal investigation into Brown's charter operations had intensified, Evans said Brown called her to the Bala Cynwyd office.
When she arrived, first Chalker and then Brown asked her about the individuals named on the contract. When Evans mentioned her aunt and her sister, Chalker asked whether she could contact them and ask them to say she had permission to use their names.
Evans said she told Chalker that she did not want to get her sister involved and that she could not ask her aunt for permission to use her name because she had died.
Chalker "got really pale," Evans said, "and she got really upset."
Later, when Evans told Brown that her aunt was dead, the defendant replied: "We don't have to worry about her."
But when Evans told Brown her aunt had died two years before she was supposed to have signed the contract, the veteran educator became upset and said, " 'Oh, my God,' or something like that."
Chalker has pleaded guilty to three counts of obstruction of justice.
The trial of Brown and two former administrators was to continue Monday in federal court.