This procedure (optionally) creates a new document in which the amplitudes from one curve in the active document are substituted for the independent variable (X values) for all other curves. This is especially useful for finding relationships between two or more measured phenomenon in a time series.
The curve whose amplitudes you want to use as the independent variable must have monotonically increasing X values, otherwise the relationship you are trying to determine might be misleading. If necessary (and appropriate) you can first sort the X values using the Sort command on the Edit menu.
DPlot will interpolate, if necessary, to find the amplitude of this curve at each X value for all other curves. If a given X value is outside the extents of that curve, this point is deleted.
After performing this operation on all curves, all new curves are sorted in increasing X order if the Sort new curves in new X order box is checked.
If the source curve had a legend, it will be used as the X axis label for the resulting plot. Otherwise the Y axis label will be used.
You can call this function from a macro or via DDE conversation from another program with the SwitchX command.

Related macro commands 
Page url:
https://www.dplot.com/help/index.htm?helpid_switch_x.htm