Sublimation is just a solid becoming a gas, without passing through the liquid state in between. It can happen under specific conditions of temperature and pressure, which of course are different for different materials.

Back to the tin question...I did some looking and I think that they seem to call it an allotropic transformation. So I suppose the verb is "allotropically transform"? YUCK! I'm not pleased with that term, I feel like there was a more elegant, maybe slightly more general, one-word term for it, which clearly I will never remember...