Hi Jaime,
Thanks for contacting Syncfusion support.
We can manually add/edit the Report parameter labels (prompt) node in RDLC definition file as shown in below screenshot. But Visual Studio RDLC designer doesn’t allow to add/edit Report parameter labels (prompt) in UI due to some RDLC compatibility.
For RDL: In ReportBuilder, you can able to add/edit the parameter name in Report Parameter property dialog box as shown in below screenshot,
Please refer to the below MSDN link for more detail,
Regards,
Yuvaraj D.