In business financing collateral is a promise to noteholders that the company is not liquidating an asset (tangible intangible or even lease out). Doesn't mean the own it.
In simple words everyone will the ask for such to ensure, they don't finance the corp and then the corp sells or leases out the collateral.
In case of BK noteholders don't own collateral, they based on priority date are owed assets they are credited prior to common share holders.
This is basic finance.