Reynolds told the Sunday Mail: "We had players with great quality at the World Cup but never showed anything in Canada.
"In the three games we were walked all over and for the boys who have been selected for the Under-21s it's a chance to redeem ourselves and show we can compete at international level.
"I definitely think the players were embarrassed by our display when we came back. We knew we hadn't turned up and had disappointed people. It felt worse because we knew we could match anyone on our day.
"Nothing clicked, nothing went right - so this is a chance to make up for it. For those who were in Canada we're lucky to get this second chance to play against the best in Europe.
"Events like that are few and far between and we didn't do ourselves justice last time.
"That's a regret the boys will have to live with.
"We knew the whole nation was watching us, as well as our families, and everyone wanted us to do well.
"It didn't go right and it was a huge disappointment. We know we let everyone down but most of all we let ourselves down."