Democrats had pitched parliamentarian Elizabeth MacDonough on legalizing millions of undocumented immigrants by making a change to the date for when undocumented immigrants within the United States can apply to adjust their legal status.

But MacDonough told Democrats that the option was a non-starter, according to a copy of the guidance obtained by The Hill. Democrats are pursuing other back-up plans with the Senate referee, according to a source familiar with Democrats’ strategy.

Changing the registry date is a “weighty policy change and our analysis of this issue is thus largely the same” as for Democrats’ previous proposal to provide legal permanent resident status to some immigrants, MacDonough told Democrats in her guidance.