This can be really hard to do after the fact because not only were these people disrespected to a degree, or blown off, if you will.
The Lone Wolf has lost trust and you have to get that back. So, starting with trust is probably the first step. How do you do that? With an admission of making a mistake…admitting that maybe that approach wasn’t the best, that you want to do things differently and move forward with involving people. Then, ask for feedback and input on how things could be different with the project, or what could have been done differently. You can also ask what could be done moving forward and follow-up on the feedback.