Certified GKH Gardening Expert
Unfortunately, the type of lily is not mentioned. The timing can depend on type for some cultivars. Some will tolerate transplanting, while others will need to be dormant before moving.
Typically, carefully moving to its new location in spring while it is growing, actively, is a safe thing to do. There are some exceptions.
This is the search page with the search terms "Lily Articles", which will help you to find some articles that you will find useful: