The replacement key will have to have to be the correct type and MUST be programmed into the security system module .. Below is a link to the instructions showing how that is done:
https://lost-car-keys-replacement.com/buick/rendezvous/
RepairPal Certified shops can diagnose and repair your 2002 Buick Rendezvous. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.
Options are locksmith or GM dealer.