Yes. If you’ve just ended an experiment, you can undo the completion and put it back to running so it can collect data again.
What happens when you undo
The experiment status changes from “Completed” back to “Running.”
The conclusion you wrote (if any) is cleared.
The test stays live on your site and starts recording visitors and conversions again. Existing data is kept; new data is added.
How to undo
Go to Experiments (your A/B tests list).
Find the completed experiment you want to reopen.
Click the ⋮ (more options) on that row.
Choose Undo.
In the confirmation dialog, confirm that you want to undo the completed experiment.
The test will move back to the “Running” section and behave like a live test again.
Limitation (free plan)
If you’re on the free plan and the test was completed more than 60 days ago, “Undo” may not be available. In that case you’ll see a message that raw data is no longer available for that test on the free plan, with an option to upgrade.
Tests completed within the last 60 days can still be undone on the free plan.
After undoing
You can change the test (e.g. variants or targeting), leave it as is, or end it again when you’re ready. Undo only reopens the test; it doesn’t delete or reset your data.