We placed an order for an assembled flex PCB.  JLC then told us that there were additional soldermask(coverlay)/copper restrictions that were not mentioned in their capabilities page, so we have to edit clearances and reupload.  Extremely inconvenient, but it is what it is.  We agreed we would replace it to their new specs. However, when JLC enable the "replace file" button, it is for the PCBA, not the PCB.  When clicked, it links us to the upload BOM/CPL page i.e the middle of the order prodcess.  When clicked and then clicked "back" as instructed, there is no way to upload and replace the PCB, instead it just makes you upload from the start, re-enter all specs etc etc.  Then, it errors out saying that there are not sufficient parts, this is because we pre-purchased the parts, but JLC thinks they're still assigned to the file to be replaced. <br> Best solution would be to make the replace file button to work.  Another solution would be to allow the JLCPCB staff to upload the replacement gerbers themselves instead of the user using the order form. <br> This kind of issue always takes up a lot of time and energy, and is holding us back from ordering more frequently on JLC.  Improving this issue would make us order more often.