You could create a weight_reset function similar to weight_init and reset the weigths:
def weight_reset(m):
    if isinstance(m, nn.Conv2d) or isinstance(m, nn.Linear):
        m.reset_parameters()

model = = nn.Sequential(
    nn.Conv2d(3, 6, 3, 1, 1),
    nn.ReLU(),
    nn.Linear(20, 3)
)

model.apply(weight_reset)

Or alternatively just create a new instance of your model.