What I'm trying to accomplish is a front-end form that allows members to update their phone numbers on file. Phone numbers are stored in their own section and attached to a member record via subsection manager in the backend.
c.f., Symphony CMS Discussion
Symphony 2.3.6 Subsection Manager 3.5.1
My initial answer sort of worked but it was reinventing the wheel. Symphony's Events can handle the scenario I jotted out above. By using the native event behavior you don't have to recode the user feedback etc.
I highly recommend this article (slightly dated) by @Brendo.
Note: references to self::ROOTELEMENT
is deprecated you should use $this->ROOTELEMENT
instead.