Accidentally put tiles over stairs and now i cannot build stairs back up

[NoseNuggets]

I have a 3x3 set of stairs that go from the surface down about 10 levels. somewhere in the middle of the stack i accidentally put new tiles over the stairs and removed them.
i was able to use the construction menu to build stairs up to get that floor re-connected, but now the floor below is separated and i cannot get down to build up, and it won't let me build down any longer.

level 39 shows up/down stairs
level 38 shows down stairs

[McFuzz]

It was inevitable.

You might have to dig a new temporary staircase in a nearby wall to get back down to that level to fix it

[Sayla Massochist]

You can create a channel down from the floor above the one in issue and and use it in order to build an upward stair to reconnect the system. Then simply mine the ramp away and floor tile the opening it made.

[NoseNuggets]

how can i get the floor looking like the rest of the smoothed floor tiles after punching a new hole for stairs or a ramp?