Opposite words for reciprocate:
excuse, owe, forgive, slight, pass over, overlook, pardon, absolve, acquit, forget, neglect.
Usage samples:
  1. Indeed, I cannot express my grief that you should have changed in so short a time from the kind, generous capitan of old times long ago to the very cruel, disobliging person of this minute, who calls me names and refuses to reciprocate kindness for kindness.
    "Looking Seaward Again", Walter Runciman.
  2. But one must reciprocate.
    "This Simian World", Clarence Day Jr..
  3. And her failure to appreciate or reciprocate my respect for the integrity of her personality is the hardest blow she can ever give to me.
    "An Anarchist Woman", Hutchins Hapgood.
  4. I heartily reciprocate this fraternal sentiment, and I am confident that you will need my assistance before I need yours: but all that I have and all that I am shall be at your service, Homer.
    "Taken by the Enemy", Oliver Optic.