If you are running interactively, running a platform other than the Distribution Platform, and are using the Show Limits() feature in JMP, all you have to do is to right click on the axis, and change the linesize and color of the Reference Lines that have been set automatically.
If your need is to do this in a script, then you will either have to not use the Show Limits() feature and just go and read the spec limits and create your own Reference Lines, or if you have the Show Limits() turned on, then yes, you will have to delete and then add back in the reference lines.
Jim