How do you change the email address that receives the requests for access?
When you are designing a SharePoint site, you might be the one that is receiving the requests for access. Once you complete your work you will probably want to transfer ownership to someone else and have them approve the requests. First check the permissions and make sure that person can approve requests. Second you need to go into the settings and change the email address that gets notified that there is a request.
When you are on a site, go to Site Settings and choose Advanced Permissions, click on the menu Settings and choose Access Requests. This will give you the email address used for requests from within that site. Change the email to the new one. It's pretty easy.