Here's the reason Patti Davis was crying on the front pages of the nation's newspapers last week: "it was an emotional moment, you know. My parents are moving away, and the house is being sold, and it's like your childhood is going out from beneath you."

It was the Reagan's goodbye to their daughter outside the house in Pacific Palisades. Cameras recorded every tear. "My mother was crying, too," Davis said. "My father was smiling, because at the moment the camera snapped, he was trying to cheer me up."

If you visited Patti Davis in her Santa Monica apartment, says a California friend, "you would have no idea who she was." There are no campaign reminders on the walls, no Hollywood memorabilia from her mother and father. Only one thing gives her away: a small black-and-white picture of Ronald Reagan, softened by that brownish-red tint you might see in an old photograph of Douglas Fairbanks.

It's of a young Reagan in his acting days, and it sits on his daughter's dresser.

Her feelings about Reagan as president, says this aspiring actress, song-writer and daughter number two, "haven't gotten unmixed yet. It's hard seeing someone you love in that type of situation and under that kind of pressure. His life really isn't his own any more."

Neither is hers. She's been besieged by interview requests since her father won the election, and she recently told her public relations firm she's tired of talking about herself. But then, her career has risen remarkably since Nov. 4 NBC has signed her to do make-for-TV movies, and she's scheduled to record an album next month. She now has, although not in any order: A manager. The public relations firm. A talent agency.

And the Secret Service. They live in her garage.

"Yes, undoubtedly it's helping my career," she says, "but on the other hand, I've been knocking around at this for a long time, and you need every break you can get. If I have any mixed feelings about it, it's that someone might not know that I've been trying to do this for a long time, and studying a long time, and going to a lot of auditions and doing a lot of little bit parts, and you know, just going through the whole thing that every body else goes through.

"somebody might think, "Well, God, she just walked right into this." Which isn't true."

Davis is 28, tall, slender, pretty and wholesome-looking. When she wears makeup and a white, silky blouse, she can look glamorous. Like yesterday, after appearing on the "Today" show, which is being broadcast this week from NBC studios in Washington. Davis had been blow-dried by the hairdresser , touched up a little by the makeup lady, then brushed again just before going on the air.

After talking six minutes with Jane Pauley, she sat down for another interview that lasted not many more. The location was a small NBC office, but there was still plenty of room for her manager in the corner and secret service agent at the door.

Q: "Were you nervous about this inauguration?"

A: "Umm hmmm, ummm hmmmm."

Q: "What were your concerns?"

A: "That my face would break out."

Q: "but really."

A: "Oh, don't know, knowing that you're going to be photographed a lot."

She's been working at the art of acting for most of her years -- first as a child who staged plays for her parents, then in drama at boarding school in Arizona, then at UCLA (although she left during her senior year) and finally, in the last few years, with bit parts on the "Love Boat," Fantasy Island" and "Vega$." She's also written a song for the Eagles rock band, and four years ago lived with the group's guitarist-composer, Bernie, Leadon.

This did not please her parents.

Q: "Are you sick of stories about how you lived -- "

A: "Yes."

In an interview, Patti Davis is very careful. In fact, she seems a lot like a good political wife. She knows how to be charming, natural and warm, yet she knows how to politely avoid the questions that might result in answers, too personal or controversial. She is not afraid to answer a question with a flat "no" and then sit quietly, not at all tempted to fill up the silence with chatter.

But then, there have been a lot of inteviews since last year's Republican Convention.

"i learn quick," she laughs. "And, I've changed a lot. I've gotten a little bit harder, which is a difficult situation, because as an artist, you can't lose your vulnerability or your sensitivity, but then, you can't let everybody have a piece of you or know everything about you. So it's a balancing act."

Friends describe her as a private person who lives, in the words of one, "a Spartan kind of artist's existence." Her apartment near the beach in Santa Nonica is a small, Spanish-style one-bedroom, tucked away on a quiet street. There's not much furniture.

"she keeps pretty much to herself, and enjoys her own company," says someone who's known her for six years. "As far as I can see, she doesn't have a lot of friends she can depend on. She's a very strong person, and she's always been really concerned about her art. Much more than making a splash, she really wants to be a responsible actress. She'd love to work with Robert De Nero."

She takes an exercise class led by Jane Fonda and seems to admire her as a role model. This has caused endless questions about Patti Davis' politics as opposed to those of her parents, but she answers most of them with: "We have agreed to disagree."

Nancy Reagan, for instance, has called premarital sex "playing house." On "60 Minutes," Davis told Mike Wallace that "I think that depends on how you fel about the person. I don't think love is." She is also in favor of abortion, although her mother isn't. As for her parents' opposition to the ERA: "I don't know how I feel about that," she told Wallace. "...I don't know, he might be right."

She isn't dating anyone in particular at the moment, although she does go to screenings with her manager, Jay Bernstein, and out for sushi with friends. She's a vegetarian; during the inaugural, she plans to eat parsley off everybody else's plate. "They always leave it," she says.

Her mother, whose maiden name of Davis she decided to use professionally, is close. The past differences between them, she adds, have been exaggerated. i

"i'll talk to her as a friend," Davis explains. "It wasn't always that way. I think mothers are more -- let'ssee, how can I put this? -- they can make that change easier from being their child to their friend. I think to a father, you're always kind of his little girl."

Growing up, that was clearly the case. "My dad was kind of a soft touch," she says. "He would say "yes" and then he'd say, "Oh, I told Patti that she could do this and this and this," and then she'd go: What ?"