unring
/(ˌ)ʌnˈrɪŋ/Now chiefly US
verb
[with object] To reverse the ringing of (a bell); chiefly used in negative contexts as an example of the impossibility of reversing or undoing an action or decision.
Origin
Mid 19th century; earliest use found in Theodore Hook (1788–1841), writer and hoaxer. From un- + ring.