How do you erase resentment?

Forgiveness

I think what's best for that is to do what Joseph Campbell was always saying "Follow your bliss", it was like his catch phrase.

Time, patience and finding your own joy.

By removing yourself from people who trigger this emotion in you and by focusing on doing things that make you feel content and satisfied with your life.

Practicing mindfulness
Gratitude
Enjoying small moments of joy ...whatever that looks like to you ...it's different for everyone

By understanding that it only spoils your mood, not theirs.

idk that you can but you can use it as a lesson to not let them do whatever again then try to focus elsewhere so you don't stew in it

With Ignorance or forgiveness.

Hate fuels it and keeps it at the surface.

Cut that source out of your life.