It’s not something I have done and I think that for true work periods all tickets have to be closed first. But there is an experimental feature called “Virtual Work Periods” which has been discussed in the V5 Beta group. Perhaps one of the admins could add you to the Beta group so you can check it out?
No virtual work periods is released it is not experimental. You can activate it with latest 5.2.3 release. I use them and they are great. I only physically close work period once a week which is required for accurate stock takes.