Update field in another form

Update field in another form

I have a form with Job_Details in it. For each job in Job_Details i have a JSA link to a JSA form. I want to make that when i click submit to create a JSA in the JSA form that it updates the JSA Complete field in Job_Details to "Yes". I have already setup that when i click the JSA link from Job Details report that is passes the Job_Number onto the JSA form. So i want to use the Job_Number from the JSA form to update the record in Job_Details with the same Job_Number to show that a JSA has been done. 

Thanks