While the pants are still in good condition (and oh-so-comfy because they are well washed and worn), the elastic has worn out and they are a real pain to unpick. On the other hand, I had a few hand-me-down short skirts which I find too unpractical for wearing with just panties underneath. So I combined the pants and skirts.
Simply snipped off the old pants elastic and sewed it to the skirts. Now Isabel can wear pants that have cute skirts attached to them!