A resale ticket appears as "pending" when the ticket has been "added to cart". I.e. someone has started to purchase this ticket. The ticket is 'held' and appears as 'unavailable' until the checkout time expires (typically 10-20 minutes), after which, the ticket is restocked if the buyer does not complete their purchase.
Ask the buyer to try again later if the ticket has not been resold.
Note: If you used the private resale link and started the checkout process, you will 'hold' this ticket. Ensure the ticket is no longer marked as "pending" before sharing the link with the buyer.
If you receive a refund confirmation email or the ticket status changes to "sold", it means this ticket has been successfully resold.