In July the SCOTUS ruled that state laws prohibiting faithless electors are constitutional.
32 states have such laws - 18 don’t.
Electors in those 18 states can change their votes to another candidate.
“Thirty-two states have some sort of faithless elector law, but only 15 of those remove, penalize or simply cancel the votes of the errant electors. The 15 are Michigan, Colorado, Utah, Arizona, Indiana, Minnesota, Montana, Nebraska, Nevada, Washington, California, New Mexico, South Carolina, Oklahoma and North Carolina. Although Maine has no such law, the secretary of state has said it has determined a faithless elector can be removed.”
- npr.org
There are two current contested states which don’t have bans for faithless electors – Pennsylvania and Georgia.
Pennsylvania - 20 votes
Georgia - 16 votes
Arizona, Michigan and Wisconsin have bans but no penalties.