Can you change built-in parameters from Type to Instance based, and vice versa? This post shows you can.
The essence of the workflow is to
- start a family with the desired template,
- add a value to the parameter,
- change the Family Category to something that doesn’t have that parameter built-in,
- switch the parameter to Instance,
- then change the Family Category back to the original
Read the more detailed version here:
http://aectechtalk.wordpress.com/2013/12/26/change-revit-voltage-parameter-from-type-to-instance/
(It is based on changing voltage parameter to Instance based for Electrical Equipment)