How do you remove a co owner

Co-owners are just that, and cannot be removed from a joint account. Co-owners have equal rights and responsibilities. One you invited someone or joined two individual accounts into one joint account, that’s the way the account will forever be.

Either co-owner may leave the joint account, but if they do, the joint account is permanently closed. Each co-owner is responsible for monthly payments until the account is paid in full.

Each former co-owner is also welcome to apply for a new individual account.

https://www.goldmansachs.com/terms-and-conditions/Apple-Card-Customer-Agreement.pdf