In reply to SKUPPAM:
You can extend ovm_report_server class and then ovverride the process_report virtual function.
Here's how I done it.
class my_report_server extends ovm_report_server;
virtual function void process_report( ovm_severity severity,
string name,
string id,
string message,
ovm_action action,
OVM_FILE file,
string filename,
int line,
string composed_message,
int verbosity_level,
ovm_report_object client
);
//compare id or message for which you want to change severity
if(id == "your_id")
severity = OVM_INFO;
super.process_report(severity,name,id,message,action,file,filename,line,composed_message,verbosity_level,client);
endfunction: process_report
endclass: my_report_server
//Then you have to set your class as default report server in your testcase
function void start_of_simulation();
ovm_report_handler report_handler = get_report_handler();
my_report_server my_server = new();
report_handler.m_glob.set_server(my_server);
endfunction
Hope this works for you