How do you change evaporator core in 2006 Buick LaCross cxl?

To change the evaporator core in a 2006 Buick Lacrosse CXL, first, disconnect the battery and remove the dashboard to access the HVAC unit. Drain the coolant and remove the A/C lines connected to the evaporator. Then, detach the HVAC assembly, remove the old evaporator core, and install the new one before reassembling the unit and reconnecting everything. Finally, refill the coolant, recharge the A/C system, and check for leaks.