Copy below script in Cicode editor and call function from button on page. Once form is displayed, you may change the system date time manually.
Timeset() cicode function is used to set system time from scada. Read help for more info on this function.

FUNCTION
SETPC_Time()
STRING Timevar,sdate,stime;
INT hform;

hform = FormNew("Set Date/Time",35,5,1);
FormInput(0,0,"Enter Date  ",sdate,10);
FormInput(0,1,"Enter Time  ",sTime,10);
FormButton(2,2,"   OK   ",0, 1);
FormButton(15,2," CANCEL ",0,2);
FormPrompt(1,3,"Note : Enter Date in DD/MM/YY format");
FormPrompt(1,4,"Note : Enter time in HH:MM:SS format");
FormGetData(hform);
FormRead(0)= 0;
TimeSet((StrToTime(stime) + StrToDate(sdate)));
END

Note :-  Make sure that Regional DATE and TIME settings in PC is set to DD/MM/YY & HH:MM:SS format. Else above code will  fail to set date and time.

Released for: Schneider Electric Ireland