[CentOS] Extending a CentOS disk without reboot

The curious thing is that a couple of weeks ago, I used parted to resize 
a GPT partition under Fedora 23, then resized the LUKS device, then the 
PV.  I didn't have to reboot.  I don't seem to be able to do the same 
thing under CentOS 7, though that test system didn't use a LUKS 
encrypted partition.

I don't know why this is possible in some circumstances and not others.  
Anyone else?