drop by (sometime)
To come over and briefly visit or converse with someone at a future period in time. If you still have questions on the material, why don't you drop by my office sometime, and we'll go over everything step by step. Be sure to drop by the next time you're in the area.
drop by
(sometime) Go to drop around (sometime).
drop by
Also, drop in or over . Pay a brief, casual, and usually unannounced visit. For example, I asked her to drop by whenever she was in the neighborhood, or Joan loves to have friends drop in, or We'd love to drop over but we haven't time on this trip. The first term dates from the first half of the 1900s; drop in is from the mid-1600s and drop over from the late 1800s.
drop by
v. To pay a casual visit to some place: He dropped by the hospital to visit his aunt. She dropped by the office during her vacation to see if she had received any important mail.