When you work HAA you agree to work 7 on and 7 off. You get vacation that you can schedule xx days in advance to be sure you get the time off. (xx varies from company to company but is usually 60 days). If you need a day or three off within 60 days you should try and find your own coverage through a trade or find someone who will work OT and you lose PTO. You shouldn't come in on Monday and say you can only 4 days and need Fri,Sat and Sun off. Thats not who this job works and your co-workers suffer for that.