How to make sleeves longer on Photoshop with generative fill?

Things have moved on  LOT since this thread was started.  New features are making Gen Fill much more useful. As always, Jesus Rameriz is the king of Photoshop's Ai functions.  Check out this video from the starting point in the link. He is using a Reference image to get way more control of the process.  So try making a suitable selection that includes the arms, and then find and apply a long sleeved shirt of the style you want, as a Reference image.  This example is remarkable.

https://youtu.be/20r75nIsJpo?si=rjnQ8WnSzNCG2xbY&t=456

The shape of the selection is important with a task like that.  Photoshop will try to fill most of the selection.  I used the lassoo tool and selected about an inch outside of the arms and just used 'Long Sleeve' as the prompt,  I tried changing that to 'long loose sleeve' but still got this tight fitting sleve as well as some hopeless results.

Hi @Lien28851630299c have you tried just entering simple prompts like "add sleeves" or "extend sleeves"? What have you tried? Do you have a sample image you can share to better explain the outcome?