Guild Wars 2

Is there anything I can do to unlearn a recipe from one character who doesn’t have any ranks in one craft and learn it on a character that does?

Unfortunately, no. You might be able to appeal to Support if the recipe in question is exceedingly rare/exclusive (for example, if you used the Ogre Sharpening Stone recipe on the wrong character, and you can only get said recipe once per account), but apart from that, your only recourse is to level up the missing crafting discipline.

I keep suggesting they should make these learned recipes account-bound instead of soulbound. I suggest you also suggest it (account-bound for this would mean that learning the ogre sharpening stone recipe on your ranger would also let your warrior make it if it had a high-enough level weaponsmith)

I actually just this very thing yesterday with the Krait Tuning Crystal recipe I received for completing the Krait collection.

They sent it back to me via mail, but were sure to let me know that this was an exception and to not expect something like this again in the future.

Sux almost as bad as having 6 extra recipes after 7 alts learned them, already.