Very, very carefully.
In all seriousness, if you can make up a spacer with a padded underside that goes over the anchor. You get a Bolt with the same thread and a large flat washer that goes over your spacer, then use the Bolt to ‘wind’ out the anchor.
You’d need to be VERY careful on a hollow body, typically with the anchors you don’t want to try and remove them once they’re in as you will slightly loosen the fit. This can cause movement and instability issues later on.