#!/bin/bash

s='title="alpha" lorem ipsum lorem ipsum name="beta" Morbi posuere metus purus name=delta Curabitur ullamcorper finibus consectetur name=sigma'

# 1st occurrence 
perl -pe 's/(title=)"?[^"\s]*"?((?:.*?\h+name=){0}.*?)\h+name="?([^"\s]+)"?/$1"$3"$2/' <<< "$s"

echo

# 2nd occurrence
perl -pe 's/(title=)"?[^"\s]*"?((?:.*?\h+name=){1}.*?)\h+name="?([^"\s]+)"?/$1"$3"$2/' <<< "$s"

echo
# 3rd occurrence 
perl -pe 's/(title=)"?[^"\s]*"?((?:.*?\h+name=){2}.*?)\h+name="?([^"\s]+)"?/$1"$3"$2/' <<< "$s"