The two fighters will clash at London's Copper Box Arena on August 20, with the winner going on to compete in the women's lightweight championship bout.
For Kolesnyk this will be her first semi-final appearance, and it will come against a familiar opponent.
The 32-year-old fought Pacheco last year during the regular season, but was only informed about the fight two weeks prior by her coaching team, and subsequently lost by knockout.
On this occasion, Kolesnyk has enjoyed far more preparation time, as she looks to mark her first PFL play-off appearance with a win.
When asked about coming to London for her fight, the Ukrainian said: "Before I go, I'm thinking it will be cool.. As soon as I get to London, I can go to Warner Brothers studio, to Kings Cross, to see Big Ben.
"But then I sit on my bed and I ask myself 'are you going on vacation? No. Are you going on a trip? No.'
"As soon as I get in London, all my focus will be on the fight. I'm not going to go anywhere as I did in my two last fights. I'm going to be totally focused on the preparation. It's not a vacation for me. For this fight depends life, not only mine but my family too.
"When god help me to win this fight, maybe I change my ticket and we stay in London more because it's a huge dream. I definitely visit more places than just Kings Cross and any other historical places which I would like to visit.
"But as soon as I land in London before the fight, people won't see me. I usually hide myself in the hotel. Because it's not a trip, it's not paid vacation. I have a task that I must do. I have my own battle, my own war and there is no time to thinking about any other things."
Kolesnyk, who is a huge Harry Potter fan, admitted she would like to meet up with someone from the film series, adding: "I'm a huge nerd about Harry Potter. I read all books since they started publish in Ukrainian.
"I have all of them and I'm a huge fan. If god helps me to meet up after the fight with somebody who's starring in Harry Potter, maybe I will be one of the happiest people ever. For myself. But now, not about me, now about the fight."
Photo Credit: Professional Fighters League