Korean office wear has gotten more interesting in the last two years and Gangnam is where you see it first. The 9-to-5 uniform used to be a sea of black suits — now it's blazers over slip skirts, knit dresses, mules instead of pumps. The formality is still there, just translated through fabric and silhouette instead of cut.
The single outfit that crosses the most office lines is a tailored cropped blazer over a satin slip skirt with a thin cami. It works for a creative agency, a financial firm, dinner after at one of the wine bars off Yeoksam. You change nothing, swap shoes maybe.
If you're doing this for actual office work and your office is more conservative, the only swap is a slightly longer blazer (mid-hip instead of cropped) and a higher-rise skirt. Otherwise the formula is the same.