Does God change his mind??

I always think about this.

In Genesis is said that God regretted creating humans, even if Genesis is a poetic and symbolic metaphor, God repented.

The Book of Jonah is all about God changing his mind on overthrowing Nineveh.

Jonah 3:10 "When God saw what they did and how they turned from their evil ways, he relented and did not bring on them the destruction he had threatened."

Sorry if I'm wrong (and I probably am) but, isn't praying asking God to change his mind about your salvation?