Chase Sapphire Reserve Downgrade Strategy

I have a CSR that I PC'ed from a CSP before the higher AF hit last year. I want to downgrade this card and re-apply for the elevated 150k SUB, but my current CSR is my main travel & lounges card.

I don't expect a denial, but if I do get denied what are my options to restore my CSR benefits? Can I downgrade, apply, and should I get denied immediately PC back up to CSR again?