Meeting behind closed doors, party members – wearing yellow caps and t-shirts bearing Museveni's image – voted overwhelmingly to scrap elections for the party secretary-general and give the chairman the right to appoint the nominee of his choice.
This means that all powers to appoint – not only the secretary-general but also the party's treasurer and their deputies – now rest with Museveni, who has been in power since 1986.
The position of secretary-general had been held by former prime minister Amama Mbabazi, who was fired by Museveni in October amid allegations that he was nursing presidential ambitions.
In amendments to the party's constitution, the secretary-general, national treasurer, deputy secretary-general and deputy national treasurer will all be fulltime party officers who shall not hold office in government or stand for national office.
"The terms of the current secretary-general and treasurer, and their deputies, cease with effect of the amendments," party spokesperson Ofwono Opondo tweeted.
This means that Mbabazi is now an ordinary party member with no exceptional powers.
Museveni said that nominees for the now-vacant positions would be named in January.
The party is expected to meet again in late 2015 to elect a candidate for 2016 presidential elections.
Posters printed for the conference already show who the candidate will be, with Museveni's picture appearing alongside the words "Sole Candidate 2016."