Closing an unused HELOC in Texas

hi, in november we opened a home equity line of credit to fund improvements to our home in austin, texas. we've never used the heloc (the balance has always been zero), and now that mortgage rates are more attractive we're interested in closing the heloc to remove the lien and instead fund the improvements with a conventional "cash-out" refinance. the total, new loan would be well under 80% of the home's appraised value, as required. we've heard different stories about whether we can close out heloc now and refinance right away, or have to wait until next november to proceed. can you advise? thanks in advance.