Increased root size partition deletion

I have root partition size of 50G.

/dev/sda1 /boot/efi
/dev/sda2 /boot
/dev/sda3 /part
- rhel-root 50G
-rhel-swap 8G
-rhel -home 200G

Here, I am trying to add /dev/sda4 partition space to rhel-root to make it to 150G.

After partition creation:

/dev/sda1 /boot/efi
/dev/sda2 /boot
/dev/sda3 /part
- rhel-root 50G
-rhel-swap 8G
-rhel -home 200G

/dev/sda4 /part 100G

I followed the below steps:
1.Use vgextend command
# vgextend rhel /dev/sda4
2.Grow the LV using lvextend.
# lvextend /dev/rhel/root /dev/sda4
3.To Grow the file system
# xfs_growfs /dev/rhel/root.

Now I want to delete the /dev/sda4 of 100G space which is added to rhel-root.
Using parted command deleted the partition 4 (/dev/sda4).
rm 4

It asked me to reboot the machine. After machine reboots, it runs into Emergency mode. I can’t able to do anything.
Here,

MY QUESTION is that we already have /dev/sda3 with root, swap, & home, why can’t machine boot from the /dev/sda3. Here I am just deleting the extra space what I added from /dev/sda4 (100G) to /dev/sda3 right.