Hi Henrique,
By definition, the PATCH method applies partial modifications to a resource, making it a lightweight option to PUT. Both methods are equivalent, but semantically, they are different.
For more details kindly check outsystems documentation
https://success.outsystems.com/Documentation/11/Extensibility_and_Integration/REST/Expose_REST_APIs/PATCH_method_on_exposed_REST_services
Best Regards
Devendra