Yeoksam after 9 p.m. is a different city. The lunch crowd is gone, the office buildings empty out, and the wine bars and small restaurants on the side streets get the second-shift crowd — people who finished work late and decided to skip going home. The outfits for this are interesting because they have to do double duty: showed up at the office in this, going to dinner in this, maybe one more place after.
The single most flexible piece here is a black slip dress with an oversized blazer thrown over. The slip handles the going-out half. The blazer handles the coming-from-work half. Switch shoes from a flat to a heel as the night progresses and you've covered the entire arc.
I included a clutch instead of a tote because if you're staying out, you've already left your real bag somewhere. Cards, phone, lipstick, key — the four-thing rule. Anything else stays home.