Recently booked rewards ticket through Aircanada website from Rio (SDU) to YYZ. My connections included airport transfer at Sao Paulo (CGH to GRU).

SDU--->CGH (3.35hrs)--->GRU--->MTL--->YYZ.

I am wondering what are my options to change the earlier flight from SDU to CGH or to GRU or any insight how long it takes to transfer from CGH to GRU by taxi ?

SDU to CGH is Azul Airline.

Thanks in advance.