Custom orders & reworks
Two different things, and they work differently.
Custom fit on a handmade piece
Every made-to-order piece can be cut to your measurements. Add them in the box on the product page when you order. No extra charge, and it doesn't change the lead time.
Reworking a vintage piece
Hemmed, dyed, taken in, trimmed. Tell her what you're imagining and she'll tell you whether the garment can take it and what it would cost.
A reworked piece has a lead time, and like everything here it is final sale — once a vintage piece has been altered for you it can't be sold to anyone else. You can cancel for a full refund any time before she starts the alteration, so say the word early if you change your mind.
Reworking something you already own
She'll do this too. Send her a photo.