GPT PMBR size mismatch (83886079 != 104857599) will be corrected by write. The backup GPT table is not on the end of the device. This problem will be corrected by write.

I'm trying to follow this solution to fix this error but when I run gdisk, I'm getting -bash: gdisk: command not found

The solution article is  Knowledge Document: GPT PMBR Size Mismatch After Increasing Disc Capacity 

Is there another method/command I can use instead of gdisk?