The following lays out the scenarios in which a clan's spot could change hands:
If a clan X retains active players who accounted for one third of their slots (6/18) and one third of their scored points then it is guaranteed to retain its spot.
If clan X splits and X does not retain both one third of their slots and of their points, another new clan Y can claim the spot if they have active players accounting for one third of that clan's slots and points. If X didn't meet the requirements, while two different clans Y and Z do and both claim the spot then the spot is awarded to neither clan and both must start from the bottom.
Say, Clan X got 90pts and needs 30pts to retain its spot in CL9. Player A, B and C played on a 3v3 tournament where they won 15pts but now only Player A is left in Clan X. In this case player A would account for 5 points(not 15)
If a player goes AWOL (or is suspended from CL), he doesn't count toward meeting the 1/3 of players requirement. None of the points he won count either. If this player was on a team, the points will be pro-rated.I don't know exactly what this stuff means regarding Blitz and Masters, however Blitz taking over Masters slot would be quite a joke to the competitive promotion relegation system imo. M'Hunters had to work hard in order to get their 3 promotions in a row and then stay in A while these guys just come out of nowhere and spam some trolly poaching games (
https://www.warzone.com/Forum/323969-blitz).
Outlaws taking over 101st spot --> The whole competitive community switched from one clan to another, leaving 101st without any competitive players to play in A of whom none contributed to the promotion.
Blitz taking over Masters spot --> Masters clan very much still exists but just some clanhoppers switched their clan.