If your sauce has split and lost the consistency of the emulsion, in order to correct the situation, add 1-2 teaspoons of lemon juice and stir vigorously. After a few seconds, the sauce will become smooth. If the sauce is not thick enough, you can thicken it by adding one by one 1 tsp olive oil, stirring constantly. Or add a little bit of breadcrumbs until they thicken.