Hi Brian:

The seller does not have to okay the retraction. eBay states the following:

"It's OK to retract a bid if...
-You accidentally enter a wrong bid amount. For instance, you bid $99.50 instead of $9.95.
(If this occurs you will need to quickly re-enter the correct bid amount).
-The description of an item you have bid on has changed significantly.
-You cannot reach the seller. This means that you have tried calling the seller and his or her phone number doesn't work, or you have tried emailing a message to the seller and it comes back undeliverable.

It's NOT OK to retract a bid if...
-You change your mind about the item.
-You decide you can't really afford it.
-You bid a little higher than you promised yourself you'd go."