Set and move flex markers in GarageBand on Mac

When you delete a flex marker, any time changes in the area around the flex marker are either removed (and the audio material returned to its original state), or reset to follow the previous flex marker or region start position and the following flex marker or region end position.

You can delete only those flex markers that were manually added or all flex edits that were carried out on the audio file, which includes audio quantisation.

You can also change the position of a flex marker in an audio region without changing the timing of the audio material before or after the flex marker.