[Pottus]

This is a really basic solution you'll surely want to add more messages and more checks etc but just to give you a idea.

Code:

CMD:setlevel(playerid, params[])
{
     new pid;
     new level;

     sscanf(params, "ui", pid, level);
    if(IsPlayerConnected(pid))
    {
        // Level between 1 and 5
       if(level >= 1 && level <= 5) 
       {
            PlayerInfo[playerid][pAdmin] = newlevel;
            SendClientMessage(playerid, 0xFF00FFFF, "Set This Users Level!");
       }
   }
}

Edit - I see a lot of people posting code with multiple returns don't get into that habit it's bad practice and makes ugly looking hard to read code.