If you are attempting to resize a volume that is being claimed by an app in your DKP cluster on AWS, you may encounter an error that resembles the following in your "describe" output:
resize volume "pvc-xxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx" by resizer "ebs.csi.aws.com" failed: rpc error: code = Internal desc = Could not resize volume "vol-x": error fetching volume modifications for "vol-x": error describing modifications in volume "vol-x": UnauthorizedOperation: You are not authorized to perform this operation.
First, ensure that your AWS IAM Policy has all of the necessary permissions by following the instructions documented here:
For this error specifically, it is likely that you are also missing the "ec2:DescribeVolumesModifications" permission in the list of "Action"s for your policy, so once you add that, you should be able to resize volumes successfully.