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Wading into this one gently...<br>
<br>
I'm assuming you're using a plugin like <a moz-do-not-send="true"
href="https://wordpress.org/plugins/social-networks-auto-poster-facebook-twitter-g/">Social
Network Auto-Poster</a> which at some point acquired an Access
Token to act on a fellow/former admin's behalf.<br>
<br>
If you can gain access to the access token, likely stored within WP
options table, then you should be able to use <a
moz-do-not-send="true"
href="https://developers.facebook.com/tools/debug/accesstoken/">this
token debugging tool</a> to determine the name of the person who
set it up.<br>
<br>
The second half of your question is less clear. If you have admin
access to a FB page then you will be able to grant access to the new
FB account that you had created. If you're asking about the access
between WordPress and the FB page, that should also be possible but
may require that you unlink/erase the current access and then
reestablish it through the account you control.<br>
<br>
The ever-evolving FB API has new permission structures, and
frequently fine tune or restrict automatic publishing capabilities,
partially growing out of major data privacy issues (Cambridge
Analytica). Before disassociating the current token, you might want
to check that publishing plugin is keeping up with the latest API
version and will continue to function as expected.<br>
<br>
If our replies are off-target then I suggest some clarification of
the plugin in use and whether a use of the term user, page, or admin
is within the sphere of WordPress or Facebook. Best of luck.<br>
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