に代わって

Trade places with
Noun + に代わって

に代わって is a phrase that means “To trade places with”. It is only used with people/sentient creatures. 
に marks the target of the substitution (The thing not doing the verb)

の代わりに may also be used in place of に代わって

See also 代わりに

Examples

• 彼に代わっていく
  I’ll go in place of him.
  
  
• 母に代わって料理する
  Cook in place of (my) mom.
  
  
• 父さんに代わって迎えに行く
  Go to get them in place of my dad.
  
  
• 先生に代わって授業を教える
  Teach the lesson in place of the teacher.
  
  
• 彼の代わりに行く
  Go in place of him.