Comment by droopyEyelids

It depends. If your employer is part of a self-funded group of other employers, then there is a group of trustees from all the employers that can approve.

If it's a 'fully insured' group plan then the insurance company is technically in charge, but your company can do an Employer-paid exception (aka carve-out reimbursement) to cover something thats getting rejected. They also have the option to purchase add-on policies to add coverage for upper class stuff like fertility treatments, weight loss drugs, or gender-affirming care.