How to merge partitions on a hard drive in Disk Utility?

Question

macOS

Hello.
About a year ago, I divided the railway into sections as needed. Now we need to put them back together. The unused partition was erased, the file system was chosen the same (FAT32), but the button for deleting or editing the size is not active. What could be the problem? Data on the second partition cannot be erased.

Answer 1

Erase the entire hard drive, if the data is not needed, there is a button on the first screen.