In Logic Pro, choose a
Do one of the following:
Drag the flex marker to the left.
The audio material is time compressed up to the preceding flex marker, the preceding tempo marker, or the region start position. The audio material is time expanded up to the following flex marker or the following tempo marker (which can also be the region end position).
Three flex markers are added: on the transient marker, on the previous transient marker, and on the following transient marker.
Logic Pro Instruments: PDF