make amends vs regrade

make amends

verb
  • To repair a relationship; to resolve an argument or fight; to make reparations or redress. 

regrade

verb
  • To regroup or reassign. 

  • To change the classification of (potentially secret documentation). 

  • To grade again, give a new grade or grading to. 

noun
  • The act or process of grading again. 

How often have the words make amends and regrade occurred in a corpus of books? (source: Google Ngram Viewer )