Here's the situation... client's firm was at url https://client.com.
Client added a partner and got a new business name and domain: client-partner.com.
I built a new site for client-partner.com and hosted it in the same hosting account as client.com. When client-partner.com went live, I re-keyed client.com's SSL certificate for client-partner.com with the plan of 301 redirecting all the client.com pages to the new pages on client-partner.com site.
The problem is that all the inbound links to pages on client.com are https. But client.com no longer has a certificate... it's now on client-partners.com. Clicking an old link to https://client.com shows that browser error that the page is not secure. The user has to add an exception in order to get through the error and get redirected to the proper page on https://client-partner.com.
Is there any way, perhaps with htaccess, to redirect all the incoming requests for https://client.com to http://client.com so that they can be properly 301 redirected to the new pages without the browser error?