Answer:
The magnitude of magnetic field decreases in comparison to previous case.
Step-by-step explanation:
Let current flowing in two conductors are
and

Magnetic field in wire,

Magnetic field due to current I1

Magnetic field due to current I2

When two parallel conductors are carrying currents in the same direction then the magnetic field will be added.

When the direction of one of the current is reversed then the magnitude of the magnetic field midway between them


Hence, the magnitude of magnetic field decreases in comparison to previous case.