A plot gimmick that may be ready to retire

They're everywhere! You can't go to the movies anymore without seeing two people switch bodies with each other! Dudley Moore did it in ``Like Father, Like Son,'' and Judge Reinhold did it in ``Vice Versa.'' You'd think that was enough - even too much - of this particular story line, which is anything but original. It goes at least as far back as the old Walt Disney movie ``Freaky Friday.''

But Hollywood never gives up a gimmick while there's a breath of life in it. So now George Burns is switching bodies in a new picture called ``18 Again!''

Mr. Burns plays an 81-year-old man whose son and grandson both work in the family business he runs. He's a happy old guy, but he misses the days of his youth. His grandson, meanwhile, isn't faring too well with the teen-age years. Bigger guys push him around at college, and he's shy with girls.

The plot twist comes at a birthday party for gramps. There's a big 81 on the birthday cake, for grandpa's age. But if you look at it from the other side, it says 18. The old man and the young man both make the same silent wish - that they could somehow be a different age - and a couple of scenes later, the switcheroo takes place. Grandpa is in junior's body, to the amazement of junior's friends, who can't figure out how such a wimp turned into the campus hotshot. Meanwhile junior is trapped in grandpa's body, which has been injured in a car accident and may not be long for this world.

For the first 10 minutes, I thought I was going to like ``18 Again!'' because it stars George Burns, one of the great entertainers of all time. He obviously has a ball playing a younger man of 81, since he's 92 in real life. But the movie writes Burns out of the story all too soon. After the early scenes, we hear his voice on the sound track, but we mostly see him lying unconscious in a hospital bed. The star of the show is junior, played by Charlie Schlatter. He's a good actor, but who wants to spend a solid hour watching him smoke cigars and deliver wisecracks in George Burns's voice?

Another nothing performance comes from Tony Roberts, who plays Burns's middle-aged son. It's fun to see Roberts outside a Woody Allen movie for once, but the story doesn't give him one interesting moment. I was beginning to wonder why he's in the movie at all, when I noticed that he and George Burns have ears of exactly the same shape. I suppose I should congratulate the filmmakers on the subtlety of their father-son casting. But can't we expect more from today's movies than characters with matching ears?

I'm being too fussy, I guess, at a time when Hollywood can't even dream up an original story. It turns out that Tom Hanks has also done the body-switch routine in a forthcoming movie called ``Big.'' If this keeps up, I can stop writing new reviews. I'll just change the names in my old ones - and who'll know the difference?