Hi,
You could implementing something along the lines of:
x = sin(linspace(0, 10*pi, 10000));
x_shift = zeros(1, numel(x));
x_shift(1:9000) = x(1001:10000);
plot(x)
hold on
plot(x_shift)
You can check more solutions from the community in this post: https://www.mathworks.com/matlabcentral/answers/45939-how-to-do-a-phase-shift-of-a-signal