Answer:  

It happened twice to two songs in the same week, November 2, 1974, on the Billboard Hot 100 chart!
STEPPIN OUT (GONNA BOOGIE TONIGHT) by Tony Orlando and Dawn peaked at #7 that week and SWEET HOME ALABAMA by Lynyrd Skynyrd peaked at #8 that week.
The following week, November 9, 1974, STEPPIN' OUT dropped completely out of the Top 40 down to #48 and SWEET HOME ALABAMA dropped out of the Top 40 down to #44! ".