Apple Logic Express 8 - Manual (Page 760)

760 Chapter 33 Working With Notation
Creating and Choosing Signature Alternatives
Signature alternatives are just that: alternative versions of all signatures on the
signature track.
To create an alternative signature track:
1 Choose a number from the Alternative pop-up menu on the Signature track.
If the signature track is not tall enough to show the Alternative menu, drag the lower
lane line.
2 Insert the desired signatures, using the methods outlined above.
No save operation is necessary.
To switch between signature alternatives:
m Choose the desired number from the Alternative pop-up menu.
All MIDI regions are affected, resulting in the appropriate changes to your score.