That should have not been necessary, during adding the stick to your setup you can choose the name freely, even to your old “thing id”.
Even if you are 100% sure that the correct port is /dev/ttyAMA0 you should double check with dmesg -T | grep tty :
pi@raspberrypi3:~ $ dmesg -T | grep tty
[Do Sep 28 09:45:25 2017] Kernel command line: 8250.nr_uarts=0 bcm2708_fb.fbwidth=656 bcm2708_fb.fbheight=416 bcm2708_fb.fbswap=1 vc_mem.mem_base=0x3dc00000 vc_mem.mem_size=0x3f000000 dwc_otg.lpm_enable=0 console=ttyS0,115200 console=tty1 root=/dev/sda2 rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait
[Do Sep 28 09:45:25 2017] console [tty1] enabled
[Do Sep 28 09:45:25 2017] 3f201000.serial: ttyAMA0 at MMIO 0x3f201000 (irq = 87, base_baud = 0) is a PL011 rev2
[Do Sep 28 09:45:35 2017] cdc_acm 1-1.4.3:1.0: ttyACM0: USB ACM device
In my case the zwave stick is attached to [Do Sep 28 09:45:35 2017] cdc_acm 1-1.4.3:1.0: ttyACM0: USB ACM device