Hi there,
Hmm... this is actually quite interesting - and more, I am quite pleased that the conversation has leant in this particular direction as, in its own circuitous way, Dirty Pair Flash did incorporate transformations, of a sort, as Rei-Lin alluded to.
Speaking as something of a measured fan of this particular franchise - having acquired the series during college - I can attest that this envisioning of the notorious Kei and Yuri did have clothing transformations. Keeping in mind the era (circa mid/late 90's) and the continuing prevalence of Sailor Moon in Japanese pop culture - and its impact upon anime and the Maho Shojo genre - Dirty Pair Flash did incorporate this influence, in its own way.
In essence, considering Kei and Yuri's role as agents of the 3WA (interstellar FBI, of sorts) in the 23rd century, the technology of the time allows for some clothing to be donned, literally at the touch of a button. When happening upon trouble, in some episodes, they would activate a small bracelet which would start this fast, near magical change in attire (apparently their official field dress) from whatever fashion they had been wearing beforehand.
This process is demonstrated by Yuri, as seen below in this cobbled collage, of her own transformation, once so activated, with a customary shot of her and the transformed Kei, ready to do as intended.
I hope this proves informative, and colours a little more on this particular niche of the TF genre, relative to the original question
.
Thanks,
Alchemical Night.