Replacing padstacks, especially within multiple subcircuits, is a tedious task because the prototype of the new padstack needs to be added in each local padstack prototype library (e.g. one per subcircuit). The PadstackReplace() action can automate this.
First argument is destination padstack, the object that is going to be changed. It is either object for a single padstack under the cursor, or selected for all selected padstacks. Both work on padstacks within subcircuits.
The second argument is source padstack, from which the prototype (geometry) is copied. It can be tool for using the via tool's padstac prototype (which is usually from the current style) or buffer which uses the first padstack found in the current buffer.