Can I bump a variant from 30% to 50% of traffic while the test is already running?

variant B is looking strong quite early and I want to reach significance faster by sending it more traffic. Currently it is a 30/70 split and I am tempted to push it to 50/50 mid-flight.

Is that safe to do while the test is live, or does changing the split mess up the results? I would rather move fast here but not if it invalidates the whole thing.