Re: For those using Google messages with RCS with iPhone owners...

Marion wrote:

I seem to remember a "cancel" mechanism of Usenet in the olden days.
Does it still exist?
 If you made a boo boo, you could cancel an article, fix it, & then resend.

Yesbut ...
In those days propagation delays were higher, so there was more time to send out the cancel, now you probably haven't got time.  Plenty of servers implement a cryptographic cancel-lock (see headers) others ignore cancels.