The Precedent of this forum seems to be that one can simply resign a position, rather than requiring it be accepted. I think the process of accepting a resignation is over-formalising the system, which is un-needed.
Precedents, when not incorporated in rules, can be overridden by either a vote in some parliamentary manuals,
Robert's Rules of Order Newly Revised, (p. 17), or by the adoption of a rule,
Mason, Section 4, 2., which is similar to the
The Standard Code. The basic rule was expressed by an article which appeared in the journal of the American Institute of Parliamentarians,
Parliamentary Journal, July, 1997, "The Role of Custom," which states, "In the absence of any other conflicting rule, custom is binding (p. 95)." The Senate could choose to, in effect, adopt a rule and decline the nomination, if it so desires.