If you have a spell prepared that has the Ritual tag, you can cast that spell as a Ritual. The Ritual version of a spell takes 10 minutes longer to cast than normal. It also doesn't expend a spell slot, which means the ritual version of a spell can't be cast at a higher level.
{
"name": "Ritual",
"page": 373,
"srd52": true,
"__prop": "variantrule",
"source": "XPHB",
"entries": [
"If you have a spell prepared that has the Ritual tag, you can cast that spell as a Ritual. The Ritual version of a spell takes 10 minutes longer to cast than normal. It also doesn't expend a spell slot, which means the ritual version of a spell can't be cast at a higher level."
],
"ruleType": "C",
"basicRules2024": true
}