publications - What to do when you have two manuscripts under review where one cites the other, but the citing paper gets accepted before the cited paper?

I submitted an article around 11 months ago to a SCI journal and another article around 5 months ago in another SCI journal. The second article cited the first article which was under review for 6 months at the time of submission of second article. Recently, we got acceptance letter for 2nd article while 1st article is still under review. What action should we take? remove the citation in 2nd article and cite the 2nd article in 1st article or we stay with the current situation. but what if our 1st article got rejection?