Cant edit PDF after sending

Our company uses fill and sign for paperwork on job sites. The employee fills in times and gets a signature, then sends to the office. 

Sometimes the times need to be changed, however the PDF is coming thru as a flat image. This hasn't previously been an issue...the new tablet we set up for a new employee is the only one with this issue. I need to be able to edit the fields afterwards. Is there a solution?