Scheduling issues are frustrating for everyone involved. I've had very similar things happen to me where directors have attempted to humiliate me in front of the cast because of scheduling conflicts. Fortunately, by now I've learned how to get the director out into the hallway so we can work it out in private when the explosions come.
The easiest way to get past scheduling issues is to put EVERYTHING in writing.
When I'm SM'ing, I like to make a calendar listing exactly what scenes are to be rehearsed on what dates and at what locations, by scene number or page numbers, including a list of actors and techs who will be needed. (When I get my hands on a script I make a spreadsheet of who is in each scene and where fights/dance #'s/songs/etc. happen so I can sort/filter for attendance planning. Excel is my best friend.) I review any notes I have in my calendar about cast absences or other scheduling issues (holidays, room conflicts, etc.). Then I email the calendar to the director for final approval, letting him/her know that it will be going out to the entire production team (including techs, designers, producer, cast, etc.) within a specified time frame and if no response from the director making a change before that time is up (generally 24 hours), he/she will be stuck with that schedule. I have also done this in writing for directors who don't use email. I make up the schedule, take it to a meeting with the director and have him/her initial it. People generally like to read things they are signing. If they object to signing it "Oh... we trust each other, why do we need to do that?" I tell them I have several versions kicking around and this way I know for sure which version is correct.

I once worked with a director who liked to plan rehearsal schedules one week at a time.

(Okay, he wanted to do it at the end of each rehearsal for the next one, but I got the producer involved because that was definitely not going to happen.) So, what we agreed to was a similar type of outline, but on a smaller scale. He gave me his plan for the following week on Wednesday night at rehearsal. I went home that night, made the schedule for the next week and emailed it to him. He would check Thursday morning before he left for work. If there was no reply from him with changes by 6:00 Thursday night, I sent it out. That way everyone knew what was agreed to and it was in WRITING. The cast and crew loved it because they knew when they needed to show up, and had a few days notice so they could plan around it.
I've had no formal training in Stage Management, but I've had a few very good directors and stage managers over the years that I've tried to learn from, and a few spectacular failures of my own to learn from. This may not work in a professional setting if there are specific rules that need to be followed, but I find it very effective in my community theatre shows. Of course, in community theatre you can probably get away with more because a competent stage manager is hard to find and directors who alienate stage managers end up having to call their own shows.