In my eagle design )I added a package from eagle lib. to my own library. I need to change the default values of tstop and tcream for this package. I was able to change the left-side tstop and tcream values and adjust accordingly. But as I tried to apply the same on the other 3 sides i am not able to do. I tried turning off the default tstop and tcream layer even that is not working. It is resetting again to 'on'.
You change those in package definition. Select 'Information'(top left in the toolbox), click on the pad and in a window that appears uncheck 'Stop' and 'Cream'. Eagle will stop generating these two layers and you can then draw whatever you need manually.
You must increase the "Limit" value in "DRC: Masks" larger than the actual via drill value. Then, command "change stop off" will works.