[Desdemona]

"How exactly does St Francis come to know that Sandyeggo wants Francis to pray for SPECIFICALLY her by name?" That is, what is the process by which Francis gains the knowledge?

I'll take a stab. You probably won't like it, but...

We don't really know for sure. It's one of those mysteries that we Catholics love so much. Only one person has ever come back from the dead, but as the saints are saints by virtue of miracles, and the miracles are done through the saints by the grace of God, the saints are with God and He is working through them. Therefore, they hear our prayers and add their voices to our appeals for help.

[RnMomof7]

BUT how do THEY know you want them to pray for you?