What would happen to sleet if the colder air below the cloud were replaced with warm air?

The temperature below the clouds does not affect the temperature of the precipitation falling.
The sleet would change state to liquid water and would fall as rain drops from the sky.
The warm air would keep the pellets in the same state, and they would continue to fall in a solid state.
If the colder air were replaced with warm air, the sleet pellets would change to snowflakes in a solid state.

Americans often speak of their country as one of several large regions.  these regions are cultural units rather than governmental units --  formed by history and geography and shaped by the economics, literature and folkways that all the parts of a region share. what makes one region different from another? a region's multicultural heritage as well as distinct demographic characteristics like age and occupation make regions different and special. within several regions, language is used differently and there are strong dialects. there are also differences in outlook and attitude based on geography.