There is provided a method for resizing a network connection in an optical transport network that supports protection switching and receives a flexible Optical channel Data (ODUflex(GFP)) signal. In addition, Hitless Adjustment of ODUflex(GFP) (HAO) procedure includes Suppress Bandwidth Resize (SBR) information that prevents a Bandwidth Resize (BWR) protocol from being initiated. Based on the SBR information, only the LCR protocol is executed at nodes located on a protection path for protection switching, except for the BWR protocol. On the other hand, both the LCR protocol and the BWR protocol are executed at nodes located on a working path.