SF_10.1, SF_10.2, SF_11.0, SF_11.1, SF_11.2, SF_12.0, SF_12.1, SF_12.2, SF_13.0, SF_13.1, SF_13.2, SF_13.3, SF_14.0, SF_14.1, SF_14.2, SF_14.3 - https://docs.sitefinity.com/for-developers-modify-document-libraries

ModifyLibraryNativeAPI.cs

using System;
using System.Linq;
using System.Text.RegularExpressions;
using Telerik.Sitefinity.Libraries.Model;
using Telerik.Sitefinity.Modules.Libraries;

namespace Telerik.Sitefinity.Documentation.CodeSnippets.DevGuide.SitefinityEssentials.Modules.MediaModules.DocumentsAndFiles.ManagingLibraries
{
    public partial class LibrariesSnippets
    {
        private void ModifyDocumentLibraryNativeAPI(Guid documentLibraryId, string newTitle)
        {
            LibrariesManager librariesManager = LibrariesManager.GetManager();

            //Get the library.
            DocumentLibrary library = librariesManager.GetDocumentLibraries().Where(b => b.Id == documentLibraryId).FirstOrDefault();

            if (library != null)
            {

                //Modify the library.
                library.Title = newTitle;
                library.LastModified = DateTime.UtcNow;
                library.Urls.Clear();
                library.UrlName = Regex.Replace(newTitle.ToLower(), @"[^\w\-\!\$\'\(\)\=\@\d_]+", "-");

                //Recompiles and validates the url of the library.
                librariesManager.RecompileAndValidateUrls(library);

                //Save the changes.
                librariesManager.SaveChanges();
            }
        }
    }
}