call back vs convoke

call back

verb
  • To telephone someone again at a more convenient time. 

  • To request someone's return. 

  • To return to a shop or residence one has previously visited. 

noun
  • Request for a second interview or audition, following a successful initial interview. 

convoke

verb
  • To call together. 

  • To convene, to cause to assemble for a meeting. 

How often have the words call back and convoke occurred in a corpus of books? (source: Google Ngram Viewer )