Is there a way to replace an existing start part with a new one in Crep Parametrics 3.0?
A start part is used like a stencil and is in no way special; any file can be used as a template - it is used only at the creation of a model to copy from and is not subject to being recopied.
This includes default geometry, parameters, et al. These can't be overwritten by copying from another part.
in your config.pro file you change the parameters below. you can use any part or assy as a start part.