DescribeValidDBInstanceModifications
You can call DescribeValidDBInstanceModifications to learn what modifications you can make to 
            your DB instance. You can use this information when you call ModifyDBInstance.
This command doesn't apply to RDS Custom.
Request Parameters
For information about the parameters that are common to all actions, see Common Parameters.
- DBInstanceIdentifier
- 
               The customer identifier or the ARN of your DB instance. Type: String Required: Yes 
Response Elements
The following element is returned by the service.
- ValidDBInstanceModificationsMessage
- 
               Information about valid modifications that you can make to your DB instance. Contains the result of a successful call to the DescribeValidDBInstanceModificationsaction. You can use this information when you callModifyDBInstance.Type: ValidDBInstanceModificationsMessage object 
Errors
For information about the errors that are common to all actions, see Common Errors.
- DBInstanceNotFound
- 
               DBInstanceIdentifierdoesn't refer to an existing DB instance.HTTP Status Code: 404 
- InvalidDBInstanceState
- 
               The DB instance isn't in a valid state. HTTP Status Code: 400 
See Also
For more information about using this API in one of the language-specific AWS SDKs, see the following: