Upgrades are designed to be usable mid-campaign, so nothing waits for a billing date.
- Open Profile → Billing.
- Make sure the cycle toggle shows the billing cycle you want.
- Click 'Choose Pro' or 'Choose Scale' on the target plan card.
- Complete the Stripe checkout.
Two things happen at once. You are charged only the prorated difference between what you already paid and the new plan for the remainder of the current period. And the credit difference is granted immediately, so an export that was blocked a minute ago can run now.
The prorated charge appears in Billing history with a 'prorated' label next to the amount, which is why the number rarely equals the plan's list price. That is expected.
Upgrading also raises your API rate limit right away, from 30 to 120 or 600 requests per minute. If an agent was throttled, no restart is needed.
Volume tiers work the same way. Moving from Scale to a 100k tier is an upgrade like any other.