passing variable for plot expression in plot() COMMAND

Dear All,

I want to pass  a variable for wave expression in plot() .

The below command gives the wave name as waveName

plot(drCreateWaveform(drCreateVec('double xList) drCreateVec('double yList)) ?expr '("waveName") )

If I want to pass a variable to ?expr '(" "), how it can be done ?

Kind Regards,