How to resolved proxmox upgrade error pve6to7 command not found

Disable proxmox commercial repo

# disable proxmox commmercial repo
sed -i "s/^deb/\#deb/" /etc/apt/sources.list.d/pve-enterprise.list

Add the proxmox community repo

# add the proxmox community repo
echo "deb http://download.proxmox.com/debian/pve $(grep "VERSION=" /etc/os-release | sed -n 's/.*(\(.*\)).*/\1/p') pve-no-subscription" > /etc/apt/sources.list.d/pve-community.list

# update software repositories
apt update
# install software updates
apt dist-upgrade -y
# clean apt cache
apt clean
# run the upgrade checklist utility, resolve any issues reported before continuing
pve6to7 --full
# update apt repositories to bullseye
sed -i 's/buster\/updates/bullseye-security/g;s/buster/bullseye/g' /etc/apt/sources.list && sed -i 's/buster\/updates/bullseye-security/g;s/buster/bullseye/g' /etc/apt/sources.list.d/pve-community.list && sed -i 's/buster\/updates/bullseye-security/g;s/buster/bullseye/g' /etc/apt/sources.list.d/pve-enterprise.list
# update software repositories
apt update
# install software updates
apt dist-upgrade -y
# clean apt cache
apt clean
# reboot
reboot now