Yes, you can relabel anyone's garments. Just make sure to follow the rules for relabeling re: country of origin, fabric content, washing instructions, etc.
Complete rules are here Threading Your Way Through the Labeling Requirements Under the Textile and Wool Acts
Easy way is any info (except their company name) on the existing label should be on your label.
http://www.t-shirtforums.com/t-shirt-tag-relabeling-finishing/
Complete rules are here Threading Your Way Through the Labeling Requirements Under the Textile and Wool Acts
Easy way is any info (except their company name) on the existing label should be on your label.
There is a whole sub-forum on relabeling