Is there a command to resize the data frame?

Although the data frame size (% or fixed pixels) can be set in manager, and the user can adjust it with the handle, is there a command to set the width? I have a workflow that opens a form in the data region and I would like to have that region resize when the workflow is run. My current approach is to design the form to fit the region, but that is less than ideal. The only commands I've seen for the data region are open and close; am I missing something? Anyone know other approches to reach the resize goal?