Rosalynn Carter's deputy press secretary said yesterday she is resigning from her $29,500-a-year job. But Ann Anderson, 42, also disclosed that the position disappears in a major reorganization of the First Lady's East Wing staff, and that she was not asked to stay.

Anderson, who came to the White House with the Carters, said the slot she fills will be restructed to provide a new position in the scheduling and press advance areas. The reshuffle is the first step in a more vigorous and visible use of Mrs. Carter in the congressional election campaigns and her own public projects, according to Mary Hoyt, press secretary to Mrs. Carter.

Under the plan, two new positions in scheduling and press advance will be substituted for slots now held by Anderson and Mrs. Carter's appointments secretary, Jane Fenderson. The latter, however, will shift into another new position as coordinator evaluting the First Lady's communities projects. Mrs. Carter's personal assistant, Madeline MacBean, will take over appointments chores.

"There will be a lot more traveling, a lot more overtime and weekend work. Even if it were something I felt qualified to do, it just seemed to me it was the time to move," said Anderson.

She said she had not been offered a chance to stay on the staff, and that under the proposed reorganization there was no area where her particular skills and experience seemed to fit.

Mary Hoyt denied that Anderson's resignation from a job that is being eliminated, in effect, amounted to being fired.

"That is not the case," said Hoyt. "Ann has known for some time about this reorganization and this is just the logical time to do it. She is very good at her speciality and I wouldn't dream of offering her a position as a scheduler. She is going to find another job will all our support and help."

Hoyt said the entire East Wing staff of 18 will be geared to help Mrs. Carter focus attention on her communities project, an effort that calls for private rather than government initiative in solving problems of the elderly, the unemployed and the mentally ill.

Hoyt said the First Lady expects to devote three days each week to social and ceremonial duties and two days to public projects. One of those days almost certainly will take her out of town. She has already set aside a dozen days in September and October to campaign for Congressional candidates. After the November elections, she is planning a cross-country tour focusing on her projects. That schedule already extends into 1979.

Hoyt said President Carter's recently-hired image builder Jerry Rafshoon "had nothing to do" with the reshuffling of Mrs. Carter's staff.

"Ever since the President's Commission on Mental Health delivered its report, Mrs. Carter has been planning her future activities. The reorganization is the results of hours and hours of planning."

Anderson's departure from Mrs. Carter's staff is the second in as many months and at least the seventh since the Carter's moved into the White House. Barbara Heinebeck, press ad-extensive travels prevented her devoting as much time to her five-year-old son as she felt she should.

Heinebeck was the third and latest black to leave the staff. Christopher Bates, an information specialist in Hoyt's press office, went to the Agriculture Department last year, as did Angla Corley, a former assistant to the director of Mrs. Carter's projects, Cathy Cade.

Others who have left Mrs. Carter's staff were Coates Redmon, former East Wing writer; Rick Hutton, former Carter family appointments secretary, and Helen Dougherty, former head of the First Lady's correspondence. Redmon left after persistent rumors of unhappiness over disparity between West and East Wing pay scales and Hutton and Dougherty due to personality clashes with members of Mrs. Carter's staff.

Hoyt said her assistant, Faith Collins, will assume the title of deputy press secretary along with some of Anderson's duties.Paul Costello, who took Heinebeck's place, will become assistant press secretary, handling some press advance work.

In the new scheduling office, Nancy Jordan, estranged wife of Carter aid Hamilton Jordan, will work as a full-time volunteer. Hoyt said there are no current plans to place here on the payroll.

Hoyt said Mrs. Carter approved the final organization plan and had been involved in its development. There was no effort to coordinate the first lady's communities project with members of President Carter's domestic staff, sometimes thought to have neglected the effort. But Hoyt indicated that the new system would offer better dialogue opportunities with the West Wing "because our responsibilities here will be more defined."

Hoyt, who has been the target of criticism in some media circles for her handling of Mrs. Carter's public presence, said the reorganization "will give me a better chance to be more responsible to the press because a lot of my coordination efforts will be handled in a different way."

Anderson worked with Hoyt at the Peace Corps in the mid-1960s and again in the Muskie presidential campaign. She was a reporter at the Nashville Tenenssean when she met her husband, author Patrick Anderson, a former Carter speechwriter. They have two children.

She dismissed any hint of a rift. "Mary Hoyt and I are friends. I always enjoyed working with her."