I've inherited and passed along more properties then I can count and learned some valuable lessons. Doing this the right way can create a seamless transition or cost you the "savings" potential and more. Here are some things I've learned.
If you have the time capacity and plan to scale up this is an invaluable experience. You will learn more then you can imagine which will pay dividends down the road. I would also recommend giving simple maintenance a try. Youtube is amazing and I guarantee a few small repairs will save you more then the cost of the PM. Also having the ability to walk tenants through something simple like resetting a garbage disposal or diagnosing a tripped GFCI.
The above comments are correct about reading through your PM agreement to ensure there aren't any associated fees. Many have a notice period or may even require you to pay out the remaining months in current leases to exit. Don't forget they still work for you until the contract ends. Many PMs will shut down once you put in your notice so you will have to stay vigilant.
They will more likely then not help with the transition. Your biggest priorities will be getting all the property and tenant information. Past/ongoing Maintenance requests, applications, leases, property condition catalogs, move in photos, relevant communication, city inspection certificates, ect. Not getting this information from your PM is not negotiable. Having a trashed house at the end of a lease and zero documentation can easily leave you on the hook for $10K for just new floors and a repaint.
Well before the transition I would also advise you walk the property and speak to the tenants. You want to inspect the current condition of the property compared to the condition catalog and ask about past or ongoing repair requests. There very well could be a list of partially repaired items. Many tenants will also send in a list of repairs or wish list after transferring PMs that you want to be prepared for.
Then being proactive with the tenants and getting everything switched over. Having a website to process payments is also key. I use apartments.com but any should work just watch out for extra tenant fees for processing payments.
Your biggest challenge will be setting up new expectations with the tenants. You very well may need to establish new ground rules. I also am in favor of presenting yourself as the manager instead of the owner. One easy way to separate yourself is to great a new google number and email for your PM company. Even creating a DBA "doing business as" will allow you to operate under a company name with little cost and hassle. If the current lease has set availability times I try to stick with those or you can see if they will sign a new lease. I would avoid trying to do a rent hike and use it as a chance to simply update contacts and simple policies.