In a situation with a Pension Plan - sole participant, QDRO for ex-spouse, who is entitled to withdraw funds at her discretion, but has not yet withdrawn her entire amount - if the participant himself reaches Normal Retirement Date and wants to draw a small distribution of a few thousand from the Plan every few months or so (Plan permits post-retirement withdrawals by active participants) - would he waive a Life Annuity, and state that he is unmarried, or must he waive the Joint and Survivor Annuity with consent of his ex-spouse? Client is adamant that spousal consent is not needed but I wonder...

QDRO should already address this.

If EE has not remarried, then he does not need spousal consent (there is no spouse!) unless the QDRO specifically states otherwise.

If EE has remarried, then spousal consent is required. But note that the QDRO should already specify what (and when) the ex-spouse gets, so that whatever is left would be subject to the spousal consent rules.

If the DRO does not specify as above, then it may not actually be a QDRO, or it may be vague and leave room for interpretation.