The so-called "retreat to the second line" means that leading cadres at or above the deputy department level retire from leading positions to non-leading positions after reaching a certain age, which is not a real retirement.
When you reach the legal retirement age, you can retire normally by going through the relevant retirement procedures.
"Retreat to the Second Line" will not change in other aspects except withdrawing from the current real power position. You can enjoy the treatment of leading cadres, but it can only be compiled, but you no longer have any real power and no longer assume post responsibilities.