Vendor clothing patterns

How in the heck do you apply the patterns to the vendors? I am thinking I have to remove all the items from the vendor and take him to a crafting table. Before I remove all the stuff, I wanted to ask here if this is the right thing to try.

 

Alchemy Table: 1 Vendor + 1 Pattern + 5 Mandrake Root

 

Yes, put the vendor on the alchemy table with 5 mandrake and the pattern using the modification recipe. People have asked for another way that avoids emptying the vendor, but it isn’t possible now.

 

Thank you very much!!!

 

Place the vendor in your inventory and all the items will automatically go to the local bank, you don't need to remove the items manually. It took me 40 minutes to restock 200 items.