Legal Question in Employment Law in California

If the employer accepts the resignation, no. Most employment is terminable at the will of either party.

Your question has no legal relevance except to unemployment, and for that purpose the answer is no. Whether the employer agrees to let you rescind the resignation and keep working is not a legal matter; it's between you and them. As Mr. Kirschbaum said, employment is terminable at will by either party, so you could have quit without notice and they could have fired you without notice, or any reason or none at all (except of course illegal discrimination, whistle blowing, etc.). So they can take you back or not and it has no legal consequences except to the issue of whether you quit or were fired. On that issue, if they choose not to take you back, you quit for unemployement purposes.