13 Going On 30 (film, 2004)
  Jenna Rink (Jennifer Garner) is an awkward 13 and wants to be grown up; 
  wakes up one morning to find she's 30 and, as film progresses, realizes
  she wants to be 13 again.  (No body swap, but similar idea)

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17 Again (film, 2009)
  Mike O'Donnell (Matthew Perry) at age 37 is separated from his wife
  and living with his best friend.  After visiting his high school to
  reminisce, he sees a mysterious disappearing janitor (!), falls into 
  the river and becomes 17 again (as played by Zac Efron). 

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18 Again! (film, 1988)
  As Jack Watson (George Burns) is blowing out his 81st birthday candles,
  he wishes to be "18 again", and switches places with grandson
  David Watson (18)(Charlie Schlatter).

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Big (film, 1988) 
  Josh Baskin (12)(David Moscow) wishes at a carnival booth to be grown up, 
  and becomes so (his adult version played by Tom Hanks). Billy Kopeche (Jared 
  Rushton) is Josh's best friend.

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Dream a Little Dream (1989)
  Coleman Ettinger (Jason Robards Jr) and teenaged Bobby Keller (Corey
  Feldman) are generational enemies who are reconciled by a "personality 
  transfusion" (this term from Motion Picture Guide).

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Freaky Friday (film, 1976)
Freaky Friday (tv film, 1995)
Freaky Friday (film, 2003)
  [from IMDb summary for 1976 version]: "A mother and daughter find their 
  personalities switched and have to live each other's lives 
  on one strange Friday." [Friday the 13th, of course.]  
  Switch is result of "unexplained magic" (in the 1976 film),
  or a "magic fortune cookie" (2003 film).

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Help! I'm a Boy (Hilfe, ich bin ein Junge)(film, 2002) 
  Emma (Sarah Hanneman) and Mickey (Nick Seidensticker) are pre-teens (about 11) 
  who swap bodies as a result of a magic spell put on them by classmate Four Eyes 
  (Philipp Blank).

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Like Father, Like Son (film, 1987)
  Dr Jack Hammond (Dudley Moore) ingests a Navajo drug and switches 
  personalities with his teenaged son Chris Hammond (Kirk Cameron) 
  Trigger (Sean Astin) is the younger Hammond's pal, who obtains the drug.

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Round the Twist (Australian Children's Television Foundation, 1989-2001) 
 
    "Imu Umi", 1 January 2000)
  [from IMDb]: "Pete [Twist (Rian McLean)] and Mr Gribble [Mark Mitchell]
  play a virtual reality game at a carnival, but something goes wrong and 
  they swap bodies." 

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Summer Switch (tv short, 1983) 
  Ben Andrews (Scott Schwartz) switches places with dad Bill Andrews (Robert
  Klein) on the way to summer camp.

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The Swap (TV film, 2016)
  Ellie O'Brien (Payton List) and her best friend Jack Malloy (Jacob Bertrand)
  get into an argument about whose life is better that gets so intense, they
  actually change places. While living each other's lives, they learn about
  roles and expectations, and gain empathy for one another. This is a pretty
  predictable latter-day morality tale served up by Disney.

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Vice Versa (film, 1988) 
  Charlie Seymour (Fred Savage), using a magical skull found on
  a trip to Thailand, wishes to trade places with dad Marshall Seymour 
  (Judge Reinhold). This is a remake of the 1948 Vice Versa, in which Paul
  Bultitude (Roger Livesey), as he is sending his son Dick Bultitude (about 14)
  (Anthony Newley) to boarding school, wishes on a magic stone that he could
  be a boy again. His wish is granted, and father trades places with his son.