The second Republican presidential debate, which will be held at the Ronald Reagan Presidential Library on September 27 in California, will air on Fox Business, according to news release from the Republican National Committee. Univision and Rumble will also partner with Fox Business on the debate.

Fox will air the first two Republican presidential primary debates. The first debate will air on Fox News on August 23 in Milwaukee.

On Wednesday, CNN obtained a copy of the RNC's candidate pledge that the party is requiring to participate in its debates. It prohibits participation in unsanctioned debates, requires candidates to support the Republican nominee in the general election and bars them from running as an independent or on another party's line.

"I agree to appear in only Primary and General Election debates that have been sanctioned by the Republican National Committee, pursuant to Rule 10(a)(11) of The Rules of the Republican Party," the pledge reads. "I acknowledge and accept that if I fail to sign this pledge or if I participate in any debate that has not been sanctioned by the Republican National Committee, I will not be eligible to participate in any further Republican National Committee sanctioned debates."

Vivek Ramaswamy and Florida Gov. Ron DeSantis have signed RNC loyalty pledges, a Republican source told CNN. Others have not yet signed, according to the source, but they are expected to this week.