In answers to When does Messages message via iMessage vs. SMS? I learned that if a contact is set up such that they have received iMessages from me, there still may be a way to force a new message I'm composing to go via SMS. I might want to do this if I suspect they are not connected to the internet but I need them to receive the current message quickly.
Question: How can I ensure or force a message I'm composing to go via SMS on my iPhone 6 in iOS 12?
Comments from 2016 (but no answers) to Force outgoing SMS instead of iMessage from an iPhone 6S+ to a specific contact who uses iPhone/iMessage? seem to say this can't be done, but that was three years ago.
This answer from 2014 points to answers about how to modify the receiving phone's situation. Here I'm asking about forcing SMS on a single, current message on the sender's phone.