Multiple accounts in To Do for iOs

Found a workaround for me that may work for others. 

I created separate todo lists for personal and work tasks in my personal account,  which I access on my iPhone.  I then shared the work to-do list with my work account by using the invite to a list function. I now seem to be able to manage and synch my My work list items from either my iPhone or the ToDo tab in my work Office 365 desktop app, without having to change the login on either. 

In theory, I should be able create lists in my work account and share them my personal account on my iPhone, but my company doesn't allow ToDo lists to be shared outside the organization. 

Not an ideal solution, but seems workable for me.