I use Terraform to set sql warehouse permissions, but it should be the same. I use the rest api for other things.

So, basically for a warehouse id, you need to pass on the entire array of users who would have access.

So, if there were 3 users with permissions and you need to revoke access for one, the array object (access_control_list in the api definition), that needs to be passed will have access defined for 2 users. The one removed from the object (in the payload) would have their access removed.

If it is only one user, it should be possible to pass on an empty array . I am not in front of my computer now, otherwise a quick test using postman would confirm this.. Let me know if can test this otherwise I can give a working sample tomorrow.