Volume fans are a little more difficult to remove as they envelop the natural lash. If they are ready to part ways with the natural lash you may be able to grip the natural lash (if it's visible) with one tweezer and just peel off the fan much like you would with a classic extension. However if there is still a very strong bond but it has grown out too much or maybe resting at an odd angle and needs to come off, there are a couple of other ways to remove. Get yourself another pair of angled tweezers (do not use your volume tweezers), press and crunch the base of the volume fan. I use my Vetus tweezers to do this and you can feel the bond give way and then they can be removed. If this doesn't work you can always peel away the lashes one by one but this is time consuming and you must make sure that you support the rest of the lashes so it's not uncomfortable and doesn't damage the natural lash.
If you really can't remove it this way then you can use your remover but be careful to apply it just to the base of the lash so it doesn't affect the rest of the set.
If you can see the natural lash you can grab and support that whilst you pull the fan apart from it.
The best way of removing lash fans is to 'crunch' them. Use another pair of curved tweezers and clamp down on the base of the fan. You should hear it crunch and then it should fall apart easily.
For stubborn lashes you can just pull them apart one lash at a time but make sure you properly support the natural lash when doing this.