If you want the ticks on your plot to show something other than the real numbers, you can either (a) change the numbers, or (b) manually specify your tick values.
To demonstrate, let me create some fake data:
x = 0:100;
fakedata = x/10;
fakedata(24:end) = sin(fakedata(24:end)-2.3)+2.3;
plot(x, fakedata)
Your two options are to either: change the X-values to something different (recommended):
plot(x-23, fakedata)
xlim([0 77])
Or manually specify your tick values:
plot(x,fakedata)
xlim([23 100]);
xticks(23:10:100);
xticklabels(0:10:77);