I'll assume you're talking about Arknights.
I call a "cosmetic alt" cases where a character gets an Alter, but it's not like anything has changed about their state.

For me, those who fall into this trope are Gavial and Eyja.
Gavial's point is literally that she doesn't change, her Alter is just new equipment for the sake of a rarity increase.
Eyja... I loved her story and you could argue she has grown, but did she change much? She came to study volcanos, she left to study volcanos but now with more parents' affirmation. Maybe it's the artist's fault for not making her look even slightly older visually. That would've been neat.
Swire is debatable, you could argue it's her LGD mode vs her business woman mode, that's at least two different emploi. She also takes over Chen's role but her Alter doesn't focus on that anyway.

Texas literally just changes clothes in the story. But I can argue it's "Siracusan Texas" vs "PenLog Texas" like Nearl is "Followers Nearl" vs "Kazimierz Nearl".

Surprisingly, Chen Alter is one of the ones I think has a good reason for it. It's Rhodes Chen vs LGD Chen. Releasing it a summer ver was the part that failed her. But hey, now we have her skin.