I had initially opened this question about changing email account.
some years ago I opened an account under my private email address. My work email address was used for all SRs and OTN access for last few years. Due to employment change recently I wanted to merge that work ID with my private email address as my OTN history is with that account. Just trying to change the work mail address to private is not allowed as that address is already in use (with this account dee_bee_eh1).
following instructions here from sunny I mailed and opened a call with support to get the accounts merged but I havent heard anything back. Regarding Email Id Change
Please read the last section of this page:
which details about changing your email address and requesting support if you have any difficulties.