Yes, this is possible. Here’s how you can edit and upload a new version of your document:
Open the matter you’re working on and click the blue "Documents" button.
In the Documents & Preview panel, find the document you want to edit, click the 3-dot menu next to it, and select Download. I’ve attached a screenshot below for reference.
Once you’ve made your edits:
Save the document on your computer.
Return to the matter, and in the Documents & Preview panel, click the 3-dot menu again next to the document.
Select Upload New Version, and upload your edited document.
If you have any questions please let me know!