Put things back on an even keel doesn't quite mean "a return to the way things were" but it does seem to suit the context quite well:
We all know what happened last month but I believe we're back on an
...getting her life back on to an even keel after their breakup had
Given that an apology is involved, wipe the slate clean might also work here.
To be fair he had one good idea which became law - wiping the slate
clean for people with very minor non-violent offences who had not
re-offended for at least ten years.
Mend fences might be best; this has the specific connotation of restoring relationships to how they were, and even has the implication of making a conciliatory gesture. According to Merriam-Webster, it means "to improve or repair a relationship that has been damaged by an argument or disagreement."
After the election, he spent a lot of time mending political fences.
Depending on the required nuance, you could also use calm the waters, or a verb like mollify, pacify or placate.
Other have suggested restore, and an addition of a few words here could help you find the right turn of phrase: restore order; restore a functional civility; or perhaps restore decorum ...these are just some of the possibilities.