Isn't it possible within kmp? Try "Alt+Y" dialog. After resyncing the sub, adjust it by using "[, ]" keys.
Or you can easily set the global sync of sub in Subtitle Explorer(Alt+Q). First, turn off the function of following subtitles("F" button there). Then, find a current subtitle section by scrolling up and down in Subtitle Explorer. If you find a matching subtitle line, select it and press "S" button there. It will adjust subtitle sync to the selected line. Again, "[, ]" keys can be used to adjust a subtle sync.
If you want to save the resynced subtitles, there is a menu("V" button).