API Dataflows - Update Dataflow

Hello, 

I am trying to set up this API:

https://learn.microsoft.com/en-us/rest/api/power-bi/dataflows/update-dataflow

In order to change the name of a dataflow.

My code: 

$body=@{
    updateDetails=@(
        @{
            name = "DTF TEST Pipeline 1.0.1"
        }
    )
}
Invoke-PowerBIRestMethod -Url "https://api.powerbi.com/v1.0/myorg/groups/4c2d4aa2-c195-4ecf-804a-be2afff547c6/dataflows/2ed4a772-827d-4d3b-87aa-6c0be92fc79f" -Method Patch -Body $body

But I have this error:

Invoke-PowerBIRestMethod : Une ou plusieurs erreurs se sont produites.
Au caractère Ligne:21 : 1
+ Invoke-PowerBIRestMethod -Url "https://api.powerbi.com/v1.0/myorg/gro ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : WriteError: (Microsoft.Power...werBIRestMethod:InvokePowerBIRestMethod) [Invoke-PowerBIRestMethod], AggregateException
    + FullyQualifiedErrorId : Une ou plusieurs erreurs se sont produites.,Microsoft.PowerBI.Commands.Profile.InvokePowerBIRestMethod
 
Invoke-PowerBIRestMethod : Encountered errors when invoking the command: {
  "code": "BadRequest",
  "message": "Bad Request",
  "details": [
    {
      "message": "Unexpected character encountered while parsing value: S. Path '', line 0, position 0.",
      "target": "dataflowUpdateInformation"
    }
  ]
}
Au caractère Ligne:21 : 1
+ Invoke-PowerBIRestMethod -Url "https://api.powerbi.com/v1.0/myorg/gro ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : WriteError: (Microsoft.Power...werBIRestMethod:InvokePowerBIRestMethod) [Invoke-PowerBIRestMethod], Exception
    + FullyQualifiedErrorId : Encountered errors when invoking the command: {
  "code": "BadRequest",
  "message": "Bad Request",
  "details": [
    {
      "message": "Unexpected character encountered while parsing value: S. Path '', line 0, position 0.",
      "target": "dataflowUpdateInformation"
    }
  ]
},Microsoft.PowerBI.Commands.Profile.InvokePowerBIRestMethod

Can you help me?

Thanks

Charline