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Perform following to update permission authentication for EBS RDS :
Login to the AWS Management Console at https://console.aws.amazon.com as root user.
Navigate to RDS console.
In the navigation pane, Click on Databases.
Click on the Database instance to be modified, click Modify.
Under the Database options choose Enable IAM DB authentication.
Click on the Continue.
Under Scheduling of modifications option select Apply Immediately.
Click on Modify Cluster.
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