Can I combine vhdx and avhdx file to save disk space?

I create a VM on my Windows 10 machine. Originally, it only has 1 vhdx file for my virtual hard disk. But now, it creates another file *.avhdx for the disk.

Is there a way to combine them? the vhdx file is 255GB and the avhdx is 139 GB.

Can you please tell me how can I safely remove the avhdx file to save space?