How to disable the multiple login in SAP?

How to  disable  the multiple  login in SAP?

How to  enable  the multiple  login in SAP?

Execute the Tcode RZ10 from the command field,  Select  the instance profile from the picture  button,  in the edit profile  select the  Extended Maintenance, then click  display

Double click over the login/disable_multi_gui_login parameter(below)

Click the Display <-> Change  button(above) to change the parameter value from the top let corner

 Now  you can change the parameter value  then click the copy button(below)

After click the  copy button, now you can  see the value changed to 1 (below)

0 to allow multiple logins