I know, this is very close to [Functions with Options][1] and/or [Function with custom Options and modified Options for built-in Symbols][2], but I don't get it.

My function looks like this one:

    myPlot[data1_, data2_, opts : OptionsPattern[]] :=
     Module[{Rescaled, dataRescaled},
      Rescaled[x_, commonZero_: False] :=
       If[commonZero,
        (* for an common zero line *)
        x - 5,
        (* normal *)
        x
        ];
      dataRescaled = Rescaled[data2];
      ListLinePlot[{data1, dataRescaled},
       FilterRules[{opts}, Options[ListLinePlot]],
       PlotLegends -> {"should not", "be the legend"}]
      ]

And this is how I want to call it:

    myPlot[
     Sin[Range[51, 100, .1]],
     Cos[Range[51, 100, .1]] + 5,
     PlotLegends -> Automatic
     ]

[![enter image description here][3]][3]

But how can I add an option "CommonZero->True"?

**EDIT:**

I edited my function this way

    myPlot[data1_, data2_, 
      opts : OptionsPattern[{ListLinePlot, Rescaled}]] :=
     Module[{Rescaled, dataRescaled},
      Options[Rescaled] = {CommonZero -> False};
      Rescaled[x_, OptionsPattern[]] :=
       If[OptionValue[CommonZero],
        (* for an common zero line *)
        x - 5,
        (* normal *)
        x
        ];
      dataRescaled = 
       Rescaled[data2, CommonZero -> OptionValue[CommonZero]];
      
      ListLinePlot[{data1, dataRescaled},
       FilterRules[{opts}, Options[ListLinePlot]],
       PlotLegends -> {"should not", "be the legend"}]
      ]

But I doubt this is the right or a nice way to do.

  [1]: https://mathematica.stackexchange.com/questions/353/functions-with-options "Functions with Options"
  [2]: https://mathematica.stackexchange.com/questions/20470/function-with-custom-options-and-modified-options-for-built-in-symbols "Function with custom Options and modified Options for built-in Symbols"
  [3]: https://i.sstatic.net/vZoIJ.png