C.R.S. § 38-30-122: No action against warrantor without notice and refusal to defend.

No right of action shall exist upon a covenant of warranty against a warrantor when possession of the premises warranted has been actually delivered to or taken by the warrantee, until the party menacing the possession of the grantee, his heirs, personal representatives, or assigns have commenced legal proceedings to obtain possession of the premises in question and the grantor, after notice, has refused to defend, at his own cost, the premises in such action.