deleted one activation on account A (all office instances must be uninstalled - they do not see the product keys and even the installation status),.
then it switches to real person and he/she is able to do it.
firstly there is some automatic "person-like-algorithm" you simply kick out by one sentence,.
You can use the "microsoft support chat".
But, although I don't like these products and their vendor very much (I do it for people who are not part of "IT crowd" and just want to pay for MS Office), I have to admit, the Microsoft got some up-votes today:.
There is really no option in the Microsoft Office account environment to transfer one activation to another accout.
As I have spent several hours looking for a solution and was ready to give it up, I would like to share the experience and result (might get handy for someone):