A method and apparatus for introducing an endless fabric loop over rolls in a paper making machine in connection with changing the fabric therein comprising an inflatable changing bag which, upon being inflated, has a vertical cross-sectional configuration in the machine direction which is substantially the same as the configuration of the intended run of the fabric loop over the rolls. The changing bag is located in its deflated condition within the fabric loop which is to be introduced over the rolls whereupon the bag is inflated with the fabric loop encircling the same. The assembly of the inflated changing bag and the encircling fabric loop is located on one side of the paper machine in the region adjacent to the rolls onto which the fabric loop is to be introduced whereupon the fabric loop is moved from over the inflated changing bag onto the paper machine so that it encircles the rolls. The changing bag is preferably provided with a plurality of interior partitions which divide the bag interior into a plurality of independent airtight compartments, each of which extends in the machine direction. As the fabric loop is pulled from the changing bag onto the rolls, the compartments are successively deflated to facilitate the introduction of the fabric loop over the rolls.