You would correct this one page of Sku Grid items at a time, using multi item actions. So I'd recommend following along with this video (but where it references Amazon, just assume Walmart) https://www.youtube.com/watch?v=Zyc-P1ZC4Z0

 

  1. In short, you'd set your grid to view 1000 items per page. 
  2. Then select Walmart from the 2nd filter on the page so that it only displays items where Walmart is the supplier 
  3. Then use Multi Item Actions to Select All Items on a Page. 
  4. Then Multi Item Actions --> Update Store Options 
  5. Select Walmart 
  6. Choose Walmart Only 
  7. And Update the Items 
  8. Repeat steps 3-7 for each page of 1000 Walmart items if you have that many.   
  9. Then you can do a Recheck ASAP https://www.youtube.com/watch?v=IdG9JArejE0 on all items under batch options and then force reprice all items in your account using batch options --> force all items to reprice https://www.youtube.com/watch?v=1zK5V3D_XGg.