Helping a child adjust when a close friend moves away

My child’s close friend is moving away, and the sadness comes in waves. One day they talk excitedly about video calls; the next they don't want to go to school because everything will feel different. I don't want to promise that online friendship will feel exactly the same, but I also want them to know the connection can continue. How have you helped a child grieve a friendship change without rushing them toward new friends as a replacement?