Hi Oliver,
I spoke to a friend in our HR Department about 2 months ago, and let her know that I had completed my name and gender changes on all of my government documents and that I wanted to complete my transition into the workplace soon thereafter. I suggested to her that there was some urgency, as my identity documents no longer matched my personnel records and were not consistent with my male presentation in the workplace. She took a day to confer and called me back, suggesting a rough timeline that would have put my 1st day on about April 1, so we decided to push out just a little, working around a few planned absences among my managers.
I asked if it would be useful for me to prepare a letter that could be used to inform our team about what I was doing and why, and she thought it would be good to do so. So I penned a one page letter, not specific but very honest, which she read to my program manager and my direct manager, saying that it went very well. Neither spoke to me about it afterwards, though, until just before my reentry.
As "D-Day" approached, she suggested that during the week before my "coming out" day." she would call a meeting of our department (~40 people) and some of the folks in other areas that I interface with, along with other area managers who worked for my boss. I was planning to leave early that day, so that I wouldn't be around after that meeting, just to avoid any disruption or controversy.
That meeting was last Wednesday (5/3), and I was packing up to leave shortly after they gathered everyone for the team meeting. After about 12 minutes, everyone filed back down to their offices, and I scurried out the door, wondering how badly it must have gone in there. I talked to her on the phone that evening, and she assured me it went very well, and that she read my letter to them as well. I took off Thursday and Friday (my normal day off), planning to reenter the workplace, finally authentically on this past Monday (5/8).
I went in on Monday, wearing a wig, a bra and a cute tunic top, with just a little bit of makeup, and lo and behold, everything went completely smoothly. No one raised an eyebrow, and we just went about business just like we do every week. I got a couple of brief encouraging emails from some of my peers, managers in other areas, and otherwise it was perfect. There were maybe 2-3 mentions of my old name or "he/him," but they were obviously just unintentional slips, and I don't think anybody slipped more than once over the whole week.
Other than occasional check-ins with my HR friend and a brief word with my boss on the way out on Friday, it was exactly a regular week, which let me settle back in without any great anxiety or fear. It was almost unreal in retrospect, but at the time it was just business as usual, so I was relaxed and completely grateful. All of my company records were brought up to date, most by Monday when I came back, so I have only a couple of things that still need to be addressed. I've been unbelievably fortunate, and hope your experience is much the same.
Erin