hy crays so, there is :
... like you said, mid-auto + manual
... step-by-step, manual intervention
an alternative would be to split your program in 2 parts, so to change the tool between programs : like this, you may avoid the "intervention" thus, is good to know how to do this sequence, but try to avoid it whenever possible, especially because the machine may restart without restoring the previous rpm ( it's just another thing between the "mil team" and "lathe team" )
also, if you wish, please check the dimensions and weigth of your tool, with those from the machine catalogue, so maybe you can avoid the manual intervention, by using a "heavy-tool" setting inside the atc
i do not recommend changing heavy tools by hand, if at least you can hold that tool long enough, without arms fatigue, and without aligning the tool in such a way, that it is clamped from the 1st time : if you can endure and keep the tool in your hand all-day-looooooong, but the machine spindle won't clamp it right from the 1st time, because of alingment issues, then you have a big chance to damage the pullstud, and also that damage will be reflected inside the pulling mechanism of your machine, and may begin to leave a mark on all the pullstuds, regardless of the tool change type : automatic or by hand; it's a gamble, is like a virus, that may spread acrros your entire toolholders; i would recomand using a gentle approach : i put the heavy tool on a piece of wood, and after that i gentle approach the spindle, from pulse-hand-wheel, and clamp it just right
of course, bt-50 is heavier than\then\whatever bt-40, and so on
i hope you find this useful / kindly