Hello,
As long as you aren't running the programs at the same time, all you have to do is change the channel that the VI points to. If you are using Traditional NI-DAQ then change the channel that is going into the "AO Config.VI". If you are using NI-DAQmx then just change the channel going into the "DAQmx Create Channel.VI" This is assuming you are using LabVIEW.
If this doesn't solve your issue, please post some more details of exactly what you are trying to accomplish and what hardware and software you are using.
Nicholas C
National Instruments
Applications Engineering