HSTS is tied to the domain (and usually subdomains), not the certificate. includeSubDomains
is included in the header if subdomains are included. However, for submission to the preload list this is required, so this will be the case with your domain.
I would recommend keeping HTTPS (see here). Therefore you should redirect HTTP to HTTPS and then continue setting the header for all HTTPS responses.
Whatever your wishes, you can update the header to set your own HSTS policy (use max-age=0
to remove HTTPS enforcement but note this must be set over HTTPS also) and then resubmit your site to the preload list for it to be updated.
If you remove HTTPS enforcement then unless your site is currently supporting HTTPS then nobody using a preload list supporting browser will be able to connect to it until your entry is updated and that browser version deployed.
So short answer is that it is possible to remove HSTS, but a) Why would you want to? and b) this will take a while and you will have to support HTTPS in the meantime.