patch it up

patch it up (with sb) AND patch things up (to become friends with someone again after a disagreement) — помириться; наладить отношения (после конфликта)

Example 1: Isn’t it time you two patched it up? (MM)

Example 2: Apparently, they’ve since patched things up with their father. (MM)

Example 3: "You had a fight with her, didn't you? That's why you're here." He smiled, a crooked smile that held no pleasure. "My broken engagement to Miss Sandra Bamfield is part of the reason I'm on this side of the ocean, I guess." Something darkened in his eyes. What was it? She wondered sickly. Some passion he still held for his fiancée? "Well, she's here, so she must think there is some chance of patching things up — not that it's any of my business, and not that I care." (Quinn Wilder, "One shining summer")

patch up relations between A and B

Related vocabulary:
[sink one's differences]
[build bridges]
[mend fences]
[pour oil on troubled waters]
[bury the hatchet]
[olive branch]
[что было — то было]
let bygones be bygones
[кто старое помянет, тому глаз вон]
[быльём поросло]
Let the dead bury their dead.