Targe can be changed by DT if the person that was tagged have made a good impression for the reason that lead to getting a tag, the only reason that can lead to tag not being removed is if the DT member is no longer active on the forum or if the member took the tag as a personal matter. Some DT can be biased and use their position as an opportunity to oppress other who are not DT. On this forum, I have seen DT drop tags on each other over personal mattersmatters,  but by right if someone is tagged for spamming and the person later change, the tag should be corrected.