What nulldogmas said, assuming you are talking about the bass instrument sound.
I've not used RX myself. But a tool such as it's music rebalance function designed to isolate things like the bass instrument sound is more likely to do a better job of pulling that out and isolate it from everything else (assuming good functioning without significant artifacts), upon which you can adjust its level, panning, EQ, dynamics, effects or whatever else.
In contrast to that, a stereo imaging tool works on the entire program content. Many stereo image manipulation tools have a multiband option built-in, which splits the frequency range of into several frequency ranges, typically three, allowing you to make separate adjustments to each band. Applying something like that to the entire mix can sometimes be useful, but applied the above case makes for a rather blunt tool, affecting everything below the chosen crossover point in addition to the low frequency content of the bass instrument itself. Also, that approach is likely to not fully address the entire range of the bass instrument sound - any fundamental frequencies or harmonics higher than the crossover frequency won't be effected.
Two different tools.
If the problem is something like the PA subwoofers being louder on one side, such that all music sources have their low bass frequencies skewed to that side, it may be more appropriate to use a multiband stereo imager on the recording without music rebalance.
Or if that's not the case and instead the bass instrument sound itself is smeared in terms of its panning location across different frequencies, yet other instruments are not, maybe do both. First isolate the bass instrument sound using music rebalance (the isolated output of which should be in stereo) then "straighten it out" using a multiband imaging tool to get it's lower and higher frequency content aligned with each other in the panning sense, and then pan that were you want it to be the mix.
A warning on stereo image manipulation which "monofies" all low frequencies- Be careful when narrowing all bass content. Doing so can be useful as a way to improve a specifically problematic recording, and is sometimes be useful in other ways, but don't mono low frequency content just because or by rote, or because that's what EDM music mixers do or whatever. Doing so is not likely to make a recording unlistenable, but a lot of the feel of space, openness and "you are there-ness" of the live performance space is conveyed by way of low frequency difference information. It's one of the things that makes great live recordings special IMHO, and that gets minimized if not thrown out entirely when monoizing all low frequency content., and you are less likely to notice the severity of that if mixing on headphones or small speakers. So use it, just don't' abuse it.