I want to draw the point before and Delete the next point

%______ This is to return to the previous point______________
app.i=app.i-1;  
            if app.i>1                
                addpoints(app.hnext,app.Cent_Viloc(app.i).Center(1),app.Cent_Viloc(app.i).Center(2))
                text(app.UIAxes,app.Cent_Viloc(app.i).Center(1)+0.2,app.Cent_Viloc(app.i).Center(2)+0.2,...
                [num2str(app.i),"Volocity : ",num2str(app.Cent_Viloc(app.i).Velocity(1))],"FontSize",10,"FontWeight",...
                "bold","Color",'y',...
                'BackgroundColor',[1 1 1])
                drawnow
            end  
%%___________________________This is to return to the next point
app.i=app.i+1;
            if app.i>1 
                addpoints(app.hnext,app.Cent_Viloc(app.i).Center(1),app.Cent_Viloc(app.i).Center(2))
                text(app.UIAxes,app.Cent_Viloc(app.i).Center(1)+0.2,app.Cent_Viloc(app.i).Center(2)+0.2,...
                    [num2str(app.i),"Volocity : ",num2str(app.Cent_Viloc(app.i).Velocity(1))],"FontSize",10,...
                    "FontWeight","bold","Color",'white',...
                    'BackgroundColor',[0.6 0.2 0.5])
                drawnow
            end 
%_________________________