OLP, LLC v. Burningham, 185 P. 3d 1138 (Utah App. 2008) is another example of why members of an LLC should put their deal down on paper (i.e. a written operating agreement). And beginning in 2009 Iowa operating agreements should contain a clause that requires all amendments be in writing. (Can you think of anything worse than an orally amended written operating agreement? Chaos!)
The concept of oral and even implied operating agreements is a law professor's construct that should remain in the classroom.
The Burningham case is a good example of two members who have a falling out over an LLC with an oral business arrangement. The upshot of the case is that Utah recognizes repudiation as a cause of action that can be maintained without challenging the existence of an LLC or lead to its dissolution.