Changing density value during thermal analysis

Hi everyone,
I need to perform a thermal analysis. A slab of solid material subjected to one side heat flux. My energy balance equation takes in account conduction and heat generation.
The conductio term is the usual term.
The heat generation term is function of the density, but the density is a function of temperature.
I think I should perform a transient analysis and manage to change the value of the density during the anlysis after each substep, at least.
Does someone know how to do it with ANSYS? It is the software that I'm trying to use.
I saw that is possible to use the function buondary conditions but the density is treated as an indipendent variable, and it seems it ca not be changed.

If you know that it could be done with other software such as ABAQUS just let me know.

Thanks.