What action to take when there is a problem with sauce?

When there is a problem with sauce, first assess the issue—whether it's too thick, too thin, or lacking flavor. For thickness, you can add a bit of liquid or broth; for thinness, simmer to reduce it or thicken with a cornstarch slurry. If it's lacking flavor, enhance it with seasonings like salt, pepper, herbs, or a splash of acid like vinegar or lemon juice. Taste as you adjust to ensure the sauce meets your desired flavor profile.