My previous setup was 3x 22TB drives one for parity.

However I recently bought new 26TB and assigned it as 2nd parity drive planning to move parity 1 to data after the rebuild is done.

Now I don't know how to proceed by moving the first party drive as a data drive and my art would to look like this :

Party 26TB Data drives 3x 22TB

I tried to reassign the days drive but unraid wanted to preclear it ? Why ? It's not need at all I know the drive is good.

Also how would i move parity 2 to one ?

Parity(1) and parity2 are different algorithms and are not interchangeable. If you want to use a drive as parity(1) instead of as parity2, you will have to rebuild it as parity(1).

If you assign a disk to a new data slot in an array that already has valid parity, Unraid must clear the disk so parity remains valid. A clear disk is all zeros so has no effect on parity.

If you want to use the new larger disk as parity(1), and use the old parity in an additional data slot, the simplest thing would be to New Config, assign disks as you want, and let it build parity(1). You can format the additional data disk (old parity) during or after parity rebuild.

Make sure when you New Config that you don't assign any data disk to any parity slot or it will be overwritten with parity.

https://docs.unraid.net/unraid-os/using-unraid-to/manage-storage/array/array-health-and-maintenance/#reset-the-array-configuration