#!/bin/bash read if then return to read

I want to make a script and after you type first command, I want to be sent back to previous.

#!/bin/bash
read -p " Please enter [x ; y ; z]: " COMMAND
if [ "$COMMAND" = x ] ; then
    echo " This is command X. "
#Then return to    read -p " Please enter [x ; y ; z]: " COMMAND

elif [ "$COMMAND" = y ]; then
    echo " This is command y. "
#Then return to    read -p " Please enter [x ; y ; z]: " COMMAND

elif [ "$COMMAND" = z ]; then
    echo " This is command z"
#Then return to    read -p " Please enter [x ; y ; z]: " COMMAND

else
    echo " Command not found! "
fi

For example if you type x , I want to be possible to type after that y or z. It can be done in same script?