Graph Builder Remove Variable

[#1]

Hello,

I am trying to use jsl to remove the x-axis variable and replace it with a different one.  It looks like I should use the GraphBuilderBox <- Remove Variable() tool, but since I change the x-axis variable multiple times, I do not know its name and would like to use the Remove Variable(Role("X"), Position(1)) method, but this does not work.  Any assistance would be appreciated.

Thank you,

Martin