ddrescue: How to restart from pass 1?

I've been trying to recover data from a 500GB WD Scorpio Blue drive I found recently that was from an old Acer laptop. I ran it for about a day before the read rate had slowed down to about 50KB/S and it had only rescued about 60GB. I then added -a100000 to the command (skip ahead if read rate falls below 100KB/S) and it rescued about 300GB in only a few hours! However, when it got to pass 3 (rescue what was skipped in pass 1 & 2) the speed had dropped to only ~20KB/S and would take about 3 months to finish. So I would like to restart from pass one, this time with -a50000 (-a is ignored in pass 3). I came across [this question](https://unix.stackexchange.com/questions/517229/ddrescue-how-to-re-run-first-pass-dont-do-reverse-yet) , however in their case they were still on pass 2, where -a isn't ignored.