Madrooster - our experience is different, I have found it very very difficult to reinstate a cancelled segment when availability is not present - either through the airline or a TA. As to bots - typically not putting in the FF number, and passport number, or incorrect birthdate will keep the bot away for enough time that you need, and need to look at it from what is the worst that can go wrong perspective and ensue you are protected. i.e. cancelling all flights before booking the alternative is probably not the order I would do it in.

Airline bots will cancel the duplicate segments that suit them the best whether ticketed or not. I have had bot cancel the ticketed segments (as in a whole paid ticket with one overlapping segment) and leave the unticketed in place. Learnt from that one!

Just saying that you should do everything in the order that causes less issue, if the airline does not play the game according to your rules.

KF