At 4 months I started putting Emma down for naps unswaddled. (I like to try sleep related things out on naptimes instead of at night).
The first week was rough. I had to rock her to sleep, lay her down, and did it multiple times before she stayed asleep. Her naps were also shorter, but that was to be expected.
I held a crocheted baby blanket between her and I, so she could hold on to it while I was rocking her and when I put her down in the crib. (I chose this blanket because I don't worry about it going over her face since it has tons of holes

)
After about a month of no swaddling during naps, we started at bedtime also. You might be able to do it at night time sooner, but Emma just wasn't ready yet.
The first 3-4 nights were rough. She woke up more. It took us longer to get her to sleep.
But, the last few nights, she has actually slept better than ever.
Good luck! I hope it goes smoothly for you. The first few days are sucky.