Create a simple plot and store the handle in a variable. Use the three different methods (dot notation, set, and structure) to change the Color property

>> x = -pi:0.01:2*pi;

>> y = sin(x);

>> ph = plot(x,y,'r*')

ph = 

 Line with properties:

 Color: [1 0 0]

 LineStyle: 'none'

 LineWidth: 0.5000

 Marker: '*'

 MarkerSize: 6

 MarkerFaceColor: 'none'

 XData: [1x943 double]

 YData: [1x943 double]

 ZData: [1x0 double]

 Show all properties

>> set(ph,'Color','g')

>> ph.Color = [1 1 0];

>> fstruct = get(ph) % to see Color only

fstruct = 

 Color: [1 1 0]