A little over a week ago I made a post a possible way to link 3% Ebates card to MR earning account. The conclusion of said post was that one of these two scenario was likely true (a) changing email address on Synchrony’s end might allow one switch from cashbaack earning Ebates account to Membership Rewards earning Ebates account (b) applying for Ebates Visa card while logged into Membership Rewards earning Ebates account will link Ebates Visa card to said Ebates account. It seems like the latter one was true, at least in my case.
I had applied for Ebates card while logged into (new) MR earning Ebates account but I had filled out the application using email address associated with (old) cashback earning Ebates account. Once I received the card, I changed my email address on Synchrony (Ebates Visa card issuer) to that associated with (new) MR earning Ebates account.
I don’t think changing email on Synchrony’s end will link your Ebates Visa card to (new) MR earning card but looks applying for Ebates card while logged into (new) MR earning Ebates account can be enough to earn MR through Ebates card.
Regardless of what I mentioned, if you want Ebates card, you should still apply for it while logged into MR earning Ebates account and provide email account associated with new account. Better be safe than sorry I guess.