Please see the tip of the day, provided by Meagan Weber, Deputy 047.
I found the help article for this to be partially helpful. This is what they direct you to do, but I didn’t find the open session here (I assume because my staff had pushed it to today and hadn’t opened a service day?) So what I ended up doing is below:
These are the options if you follow step 1, but it was only showing me completed sessions.
I went into Office Management and down at the bottom, found “view open sessions” and filtered by the staff member I was looking for, found the session ID I needed, and was able to follow steps 3 and 4 from the Help article.