[otrs] "Apache" ownership of dtl files I am not permitted to edit

Hi I have lately been unable to edit some dtl files which I have edited before. Apparently this is because the onwership of the files is "Apache" (with "rw-r--r--" permissions) and only the superuser with root acces can edit them. Since I have edited these files before, I am at a loss to understand what has occurred - whether the ownership of those files has changed after I have edited them, or whether changes to the SysConfig front end changes the ownership of these files. Has anyone else experienced such unforeseen changes of file ownership/permissions and have a plausible explanation for why they might occur? And what I can possibly do about the situation -  I need to edit some of those files! Many thanks Lev