Hi @Anonymous,
Hope you are well. 
Further to what @L.Maas suggested, which is exactly where you change it, I would like to add the following which gets overlooked.
If you have 100x Windows already tagged with say 10mm leaders and want everything to be 5mm leaders. Then you select all instances in the view, delete it, then go to Annotate >> Tag >> TAG ALL, then follow the image below:

I hope this helps! 
Rudi Roux
MSc | Digital Engineering Manager
LinkedIn
Revit Mechanical & Electrical Systems 2018 Certified Professional | Revit MEP & Architecture 2015 Certified Professional
AutoCAD 2015 Certified Professional | Autodesk Building Performance Analysis (BPA) Certificate
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