A AI can literally theoretically change from being not sentient to being so if it gains enough information in a certain way. As for the specific way? No clue cause it hasn’t been found yet. But in data gathering and self improvement a AI could become sentient if the creators didn’t but some limits or if the creators programmed the self improvement in a certain way.

Would it truly be sentient? Unknown. But what is for certain is even if the AI isn’t sentient but has gained enough information to respond in any circumstance it will seem as if it is. Except for the true creative skills of course. Kinda have to be truly sentient to create brand new detailed ideas and stuff.