How to Review Pending ASM Changes

Unfortunately there is no report which will show all the changes pending. Every time policy is applied a new version history is created. So what you can do is look at the History list for the policies to determine last apply time and then filter the audit log based on that time and look for add/delete/update events. That will be what's currently pending. An alternate method would be to restore the previous version from history but create a new policy. Then use the policy diff feature to compare the two. This option will allow to see all policy differences and merge if necessary and apply.

It is not possible to cancel pending changes. If you don't want them to take affect you must manually undo them but you will still need to apply policy. Or you could restore the previous version from history to roll back all pending changes.