Standard cells are critical primitives of modern integrated circuits. Designing standard cells requires time-consuming manual optimization. Within a standard cell library, designers resize standard cells with the same functionality for different drive strengths. Building up all the layouts of all drive strengths from scratch introduces a lot of repetitive and redundant work, especially in routing. We propose a standard cell resizing framework to migrate a layout to another drive strength by imitating the routing of the existing layout. Experimental results demonstrate that our framework is capable of synthesizing layouts with competitive performance with the manual layouts on an industrial standard cell library.