You can try adding more liquid to dilute the added salt.
If that thins it too much, dice a potato finely and when cooked, purée it.
Just cooking a potato in it and taking it out later may work if it’s only a little too much salt. But the problem is that it’s rather inexact.
Diluting a little, tasting, and diluting more if necessary gives you more control over the process and the ability to fine tune it.
Since this is a cream type soup rather than a broth type, it’s easier to thicken it back up as many cream soups routinely add pureed potatoes as a normal part of the recipe.
If you have them on hand, you could also use potato flakes a little at a time until desired thickness is reached.