Change signal polarity in NI9401 and NI9472

[bitao]

Hi,
how can I change the polarity of a digital signal in a DAQmx with NI9401 and NI9472 modules? Is there any example you guys could send me? Is it possible to change the polarity with a VI?
tks

[bitao]

One more thing, I am dealing with an output signal.
tks

[bitao]

Hello,
actually I want to switch voltage from - to + and vice-versa so that I can open and close a latch solenoid valve according to determined conditions.
Sorry for not have being so clear.
tks