dissolve, thaw, unfreeze, unthaw, dethaw, melt(verb)

become or cause to become soft or liquid

"The sun melted the ice"; "the ice thawed"; "the ice cream melted"; "The heat melted the wax"; "The giant iceberg dissolved over the years during the global warming phase"; "dethaw the meat"

unthaw(Verb)

To not thaw; to (re-)freeze or remain frozen.

unthaw(Verb)

To thaw out, to unfreeze; to become soft (of something which had been frozen).