What is basically the mechanism that hydrogen carbonate is reabsorbed

First carbonic anhydrase II breaks H+ and HCO3- inside the cell, then there is an exchange of H+ being secreted and Na+ being reabsorbed H+ then reacts with HCO3- in the lumen to form H2CO3 where membrane bound carbonic anhydrase IV to facilitate the formation of H20 and CO2 This then enters the cell where using carbonic anhydrase II it forms HCO3- and H+ and the cycle restarts HCO3- then leaves the cell into the blood via the 3HCO3--Na+ symporter