Synchronized integration is an option in Skyline that allows integration in a single replicate to be applied to others. It can be accessed either by right-clicking on a chromatogram to bring up the context menu or through Edit > Integration > Synchronize Integration.
This will bring up the Synchronized Integration dialog, which allows you to select which replicates should be synchronized.
If annotations are available in the document, groups of replicates to be synchronized can also be chosen.
If predicted retention times are auto-calculated, you may align times to the predicted retention times. Similarly, if retention time alignments are available for a data file, you may align times to that file. (This is the same as selecting "Show <retention time predictor> Score" or "Align Times to <file>" from the chromatogram context menu)
Once synchronized integration is enabled, any integration change (manual integration, clicking a peak, removing a peak) will be applied to the selected set.
Note that the retention times may not be exactly the same across synchronized replicates if there are not peaks at the same times. The nearest peaks are used in this case.