How to restore HDD partition size?

Question

Hard disks

In general, there were 2 partitions on one HDD. Since those who use the computer are completely unqualified in this matter, they used only the 1st section and occupy it all the time, while the second remained completely empty.
It was decided to merge 2 partitions into 1. It seems that everything is simple, but after the merge operation is completed in Acronis Disk Director (the operation was completed successfully), win7 itself still does not see the new disk size.
chkdsk /f /r didn't work.
This is how the disk is displayed in Explorer

And this is how it is in the standard Disk Management utility