Establish a day of the year when neighbors, coworkers, ex-friends, etc., bury grudges between each other in a non-religious customary way.
Establish an international holiday when people bury grudges and mend relationships with neighbors, coworkers, and ex-friends.
People would embrace the tradition similarly to how Halloween became established worldwide because it's tied to a fun custom, or how kissing under the mistletoe is still perpetuated for a similar reason.
For the holiday to become established it needs a traditional and widely accepted way of extending the hand of peace. For example, people could show up on the doorstep of their nemesis and:
knock in a unique pattern
when the door opens the visitor extends the hand, holding an olive branch with a white ribbon
if the recipient accepts, no words need to be spoken, just a handshake and a hug
What then? It feels like something is missing:)
Conditional work free day
It is possible for employers to offer employees a work-free day, but only if they request it beforehand and specify with whom they intend to mend their relationship.