rope off
To prevent people from entering some place or area by erecting a barrier of rope suspended by a series of poles. A noun or pronoun can be used between "rope" and "off." They don't usually rope the VIP section of the bar off like this—someone really important must be coming in tonight. We'll need to rope off this area until the guests arrive.
rope something off
to isolate something with a rope barrier. The police roped the scene of the accident off. The police roped off the scene of the accident.
rope off
v. To restrict or reserve some location or area by encircling it with rope: The ushers roped off the first three rows of seats for special guests. The guards roped the stairway off.