Yes - but only the PicoVNA 108, not the PicoVNA 106.

In most circumstances, a vector network analyzer stimulates a device port in signal frequency steps and measures all the ports at the same frequency steps. However, there are applications where you need to measure at harmonics of the stimulus. There are also applications, around frequency mixer devices, where you need to measure at a frequency (the intermediate frequency, or IF) that is offset from the stimulus