How can I retract a transfer that hasn't settled yet?

Complete a new transfer before the earlier transfer settles.

The newer transfer replaces the earlier transfer and invalidates it.

Because Zucoin uses two-way transaction confirmation, a transfer is not final until both parties have confirmed it, giving you time to supersede an unwanted transfer with a new one.

More on this topic:

Do transfers still expire automatically?

How do transactions work?

What are the benefits of 2-way transaction authentication?