Actually, I wanted to know how to get the screen shown in the post above to come up again, and let me set all the default dashboard settings. If I add the "Getting Started for..." panel as noted above, I don't end up with the same experience as a user seems to get when they first see the selection box and make a choice. 

The reason this came up was because an executive had selected the executive view, and then had questions about that view for me (e.g. what does that little chart second down from the right mean). What I wanted to do was to be able to reset my setting to the default executive view so that I could quickly answer his questions. However, there did not seem to be a way to get back to that initial state that shows the screen above, where you can select a default set up. - Instead I had to find time on his schedule and mine, to stop by and look at the layout he had so that I would know what he meant when he referred to the position of something, rather than the name of something.

Additionally, after that experience I have gotten similar questions from other new Rally users in my company (I am the Rally Admin) about the other views as well. Rather than help everyone individually, I would like to create a training video that could show folks what the different views look like, and how they could use them - and of course I would like screenshots that I could put on our internal wiki as well, that illustrate what the default layout looks like in Rally for each of those choice.

... So, back to the original question - once the role has been initially set, how can you change it?

In the web service API, on the User, I can see there is a Role (and I can query it and see my default "role"), but it is "Read Only", so I cannot modify it through the API. Since there is the ability to initially set the Role, there must be a way to change the role value - but if it is not through the API, then I assume there must be some way through Rally to change the role.