Yes, you can upgrade or downgrade your plan at any time from your account settings under "Subscription." Changes take effect according to your current billing cycle.
What changes with the plan:
Moving between Starter and Pro changes more than the credit amount:
Upgrading to Pro unlocks full warning details (instead of issue titles only), research exports, and credit rollover. Warning details for already-generated leads become visible immediately.
Downgrading to Starter hides warning details, disables research exports, and stops credit rollover entirely: from your next renewal on, your remaining balance, including top-up pack credits, expires each month.
What happens to your credits:
When downgrading within Pro tiers, you won't lose credits immediately, but your credit cap shrinks next month. If your balance exceeds the new plan's cap (3x monthly allocation) on renewal, your balance is trimmed to that cap and you'll stop receiving new credits until it drops below the limit.
When upgrading, your credit cap increases to 3x your new monthly plan amount, allowing you to accumulate more credits.
Best practice: Spend or export excess credits before your new billing cycle begins to avoid hitting the cap when downgrading, and use up your balance before a downgrade to Starter takes effect.