We are attempting to use the native approval routing for our expense reports and have had a few issues. One is if the role has more than create they are able to approve their own expenses and override the supervisor. We did find the solution to this issue is setting the permission level to create. With those permissions it would not allow us to reject an expense report however you can approve it. What am i missing within the setup to achieve this outcome.

1) Users should not be able to approve their own expense report, but still have the ability to void it in the event they need to update. No matter what center their role is using.