Time, Tempo, and Meter : Change Meter : Change Meter Options : Realign
 
Realign
The Realign controls let you choose which items to realign after a meter change has been made. You can choose to realign meter events, or choose to realign meter and tempo events, tick-based markers and tracks, and also all or none of the sample-based markers and tracks.
Meter Ruler Only
Applies the meter change and realigns only the Meter ruler. All other rulers and tracks are unaffected.
Meter, Tempo, Key, and Chord Rulers, all Tick-Based Markers and Tracks, and Sample-Based Markers and Tracks
Applies the meter change and realigns the Meter, Tempo, Key, and Chord rulers, and all tick-based markers and tracks. Using the pop-up menu, you can also choose to realign All or No sample-based markers and tracks. Time is inserted or deleted as needed at the end of the selection to preserve the alignment of material following the selection.