There are a few possible antidotes. The flavor of lemon often mutes salt, so if it’s not too, too salty, you could add a little lemon juice, bit by bit, and taste to see if that relieves the problem without adding enough flavor to make your sauce taste lemony.
Another trick is to add a skinned quartered potato or two to a sauce or stew and let it cook for 15 to 20 minutes before removing the potatoes. They will absorb some of the liquid and seasoning, cutting the salt, and you may want to replace the liquid you removed, as well, thereby diluting the salt further.
The more drastic solution, of course, is to increase the volume of most or all of the other ingredients to catch up to the amount of salt present. It’s still less drastic than throwing the whole thing out….