I don't think there's a procedure for you're searching to achieve. The way that I did it when I had problems with the integration between the two, is to treat the integration as broken and remove it manually, so you can add it back later, on the other machine.
If I remember correctly, there was a procedure for clearing a faulty integration between Spectrum and PC. There's a db on the PC that stores all the information required for the integration, it's called netqos. There are several tables that store information on the integrations. On the OneClick server, there's a netqos_integ database that stores the information on the spectrum side. You'd have to drop that altogether.
If you want, you can try to modify directly on the db the hostname/ip of the machine that you're pointing to. That would not take care of all other steps that would be done if a new integration would be set. So I don't really recommend doing this, as you might end up with a faulty integration you'd have to do the integration from scratch.
The only information that is exchanged between PC and SPECTRUM is actually the elements monitored and their current life cycle status. PC sends the IP domains to SPECTRUM. I did the removal and reconfiguration of the integration several times, without loosing any data, as the devices once discovered in PM, they don't get deleted. You'd have to be careful however of adding spectrum devices to their corresponding IP domains, once the integration is reconfigured. But If you're talking about a lab environment, that shouldn't be a problem.
For the PC, there's a permission that you need to add, in order for deleting data sources. It's off by default, even for Administrators. Go to Adminstration->Roles->Administrator, select Performance Center in the list, Edit and add the "Delete Data Sources" right to Administrator role. You'll be able to delete the configured Spectrum data source.
Actually this would be your best choice, free of all problems: remove the existing integration and configure it once more on the new machine.