bit.ly Paid Feature
This is a feature available only to paid accounts.
Excerpt from bit.ly:
With a paid subscription, you can edit the link destination by entering a different target URL. There is a monthly limit of how many redirects you can edit per month based on the type of link—a custom link or a bit.ly link—and your subscription plan.
A redirected link also counts as a new link, meaning it counts against your monthly link limit. If you hit your link limit, you won't be able to redirect any links until the start of the next month.
To edit the destination of the link:
- Log in to your Bitly account.
- Click Links in the left sidebar.
Select the link you would like to edit.
Click Redirect.
Enter the new target URL.
Click Save.
For more info see:
How do I redirect a short link?