My project got shut down a month ago, and it may restart in another 3 weeks. I have about 20% of work left to do.

I want to update my project schedule to show the weeks of interrupted work, as well as an assumed re-start date to project remaining durations/finish date.

Is there a way to do this? I've been playing with splits but I can't figure how to make the re-start date 3 weeks from now.