Redefining a single predicate

[ArnonHevlin]

Is it possible to redefine a single predicate?

For example for the program:

pyDatalog.load("""
    +A(2)
    +A(3)
    B(X) <= A(X)
    +B(4)
""")

Is there a way to redefine B so it will be empty (without changing A)?