A generalized version of Holmstedt's formula for the K-functional

Let $(A_0,A_1)$ be a compatible couple of quasi-normed spaces, and let ${\mathrm{\Phi }}_0$ and ${\mathrm{\Phi }}_1$ be two general parameters of $K$-interpolation method. We compute $K$-functional for the couple $((A_0,A_1{)}_{{\mathrm{\Phi }}_0},(A_0,A_1{)}_{{\mathrm{\Phi }}_1})$ in terms of $K$-functional for the couple $(A_0,A_1)$.