A referendum can overturn the city council decision from September 21.
The city of Louisville has a comprehensive guideline for creating a citizen initiative. A referendum would follow a similar process but require half the signatures.
REFERENDUM TIMELINE
C.R.S. 31-11-100
City Council holds first and second reading on an ordinance.
If approved on second reading, the ordinance to be published in the newspaper triggering the 30-day wait period.
In that 30 days petitioners must
get the petition language and format approved by the Clerk’s Office
gather signatures from 2.5% of the registered electors (2.5% is the Charter requirement). That number would be based on the number of registered voters on the day of publication of the ordinance
submit petitions to the Clerk’s Office
City Clerk’s Office has 30 days to determine if the petition is sufficient
If petition is determined to not be sufficient, the petitioners have 15 days to cure the petition (Charter Section 7-3a)
Clerk must make a written determination on the refiled petition within 4 days of submission. (Charter Section 7-3b)
Any protest concerning the refiled petition shall be filed within 5 days of the refiling date (Charter Section 7-4b)
A protest may be filed by any registered voted within 40 days after the petition is filed. Grounds for protest may include failure of any portion of a petition or circulator affidavit to meet the statutory requirements.
Assuming the petitions are sufficient the item is referred back to Council for reconsideration. Council can repeal the ordinance or send the question to a special election.
Should a petition be verified and Council sends it to a vote, the City must hold the special election no earlier than 60 days and not later than 150 days from the reconsideration date. Special elections shall be held on any Tuesday designated by ordinance or resolution of the governing body. No special election shall be held within the ninety (90) days preceding a regular election and nor shall any special election be held within the thirty-two (32) days before or after the date of a primary, general, or congressional vacancy election. C.R.S. 31-10-108
The City Clerk shall hold at least one (1) public hearing prior to setting the ballot title for a referred ordinance and shall take into consideration any comments received at the public hearing in setting the title. (Charter Section 7-4c)
For a special election the City would follow the same process the County uses for the November elections including printing ballots, sending to oversees voters and local voters, hiring election judges, completing signature verification on mail in ballots, and procuring machines and software for ballot counting