HELP: How to change tubes in shanling T-100A


I bought a shanling T-100A and want to replace the stock tubes.I'm able to remove the top screws to remove the first cage but don't know how to remove the bottom one.Kindly help me if anyone knows how to.

Thanks in advance.
I believe that the top ring is the only one that is easily removed. Reach into the base of the tube, gently rock back and forth. Replace stock tubes with Western Electrics. If you don't use headphones,replace only the two on the left