Looking on the internet deeply has found these results:

Drop by at your office is the most popular phrase on the web.

Drop at your office 1142,000 results on the web	Drop by at your office 1211,000 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
Drop by the office for more details. Or I could have someone drop it into your office if that's more convenient. Dr. Brennan, I just thought I'd drop by your office before I leave. All right, what time should I drop her off at your office? Once he drops that office act, he is awful funny. Don't drop by my office. Drop by my office this week. OK, job or no job, you can't drop your office. I need you.	Drop by the office for more details. And they want him to be sure to drop by the office for an interview. Drop by my office this week. Drop by the office. Tomorrow. Seeing as you never drop by my office I thought I'd pop up for a visit. On an unrelated note, if anybody has an interesting anecdote that is not boring and easy to memorize, please drop by my office before I leave. Don't drop by my office. Dr. Brennan, I just thought I'd drop by your office before I leave.

Drop at your office

1142,000 results on the web

Drop by at your office

1211,000 results on the web

More popular!

Drop by the office for more details.
And they want him to be sure to drop by the office for an interview.
Drop by my office this week.
Drop by the office. Tomorrow.
Seeing as you never drop by my office I thought I'd pop up for a visit.
On an unrelated note, if anybody has an interesting anecdote that is not boring and easy to memorize, please drop by my office before I leave.
Don't drop by my office.
Dr. Brennan, I just thought I'd drop by your office before I leave.