cryptsetup-reencrypt: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On CentOS possible default full paths are:

/sbin/cryptsetup-reencrypt - from package: cryptsetup-reencrypt

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/sbin/cryptsetup-reencrypt - from package: cryptsetup-bin

You may install the required package with command apt-get install {package}

Error in other languages:
cryptsetup-reencrypt: bevel nie gevind nie
cryptsetup-reencrypt: comandă negăsită
cryptsetup-reencrypt: comando não encontrado
cryptsetup-reencrypt: commande introuvable
cryptsetup-reencrypt: command not found
cryptsetup-reencrypt: käsku ei ole
cryptsetup-reencrypt: không tìm thấy lệnh
cryptsetup-reencrypt: komanda nerasta
cryptsetup-reencrypt: Kommando nicht gefunden.
cryptsetup-reencrypt: kommandot finns inte
cryptsetup-reencrypt: komut yok
cryptsetup-reencrypt: nie znaleziono polecenia
cryptsetup-reencrypt: níor aimsíodh an t-ordú
cryptsetup-reencrypt: no se encontró la orden
cryptsetup-reencrypt: no s'ha trobat l'ordre
cryptsetup-reencrypt: opdracht niet gevonden
cryptsetup-reencrypt: parancs nem található
cryptsetup-reencrypt: perintah tidak ditemukan
cryptsetup-reencrypt: príkaz nenájdený
cryptsetup-reencrypt: příkaz nenalezen
cryptsetup-reencrypt: команда не найдена
cryptsetup-reencrypt: командата не е открита
cryptsetup-reencrypt: 命令找不到
cryptsetup-reencrypt: コマンドが見つかりません