Since v10, I think, new models defaulted to having a link to a default model that contained helpful functions. So you could, for example, define the Working Days for your organization in one model on a shared drive, and then get all the other models to fetch the WorkingDays interval function from there. There's no harm in a missing reference to the xmod, as long as your models don't depend on any imported functions. If you want to put a copy there, there's one adapted on my blog at http://www.greenbar.info/examples/functions.xmod which you're welcome to download. Or you can edit your model to delete the reference to the external model altogether.
And yes, you can just save, I think, as you can't save changes back to xmod, but save as will work fine.
Hello TFreeze, nothing quite so simple... Open the model, go to the Table, enter Table Design mode, click on the f(x) icon for functions, and then go into Manage external functions, which should bring up the External Functions library, from where you can Remove External Model... Anyone out there using these, watch out tor "weak" links being deprecated - links are either "strong" or "none" now. Best wishes, Olly