My subcription of SLES 12 SP 4 has ended and I would like to extend it further. How can I do that and at what feem
@Ernest Hi and welcome to the Forum 
You need to contact a reseller in your locale and get an electronic registration code. Then visit SCC (https://scc.suse.com/) and add the registration code to enable it, then re-register your system with SUSEConnect, your email and the new code.