If you have not yet read through the Landlord Tenant Laws for the State/County/City where the rental property is located, be sure you have read through the Laws thoroughly.

I suggest that you discuss your situation with an experienced Landlord Tenant Attorney (who practices in the same State/County/City as your rental property) who can take a look at your lease agreement, 3 day notice and any other paperwork you have to verify that you have properly followed the Laws.  The Kansas Landlord Tenant Law prevents a Landlord from using "self-eviction" and there are very specific proceedures for Landlords to follow when determining if a property has been abandoned and, then, if so, how to handle the abandoned property.  You really have to be careful to be sure you protect yourself.  Unfortunately, some Tenants are well-versed on the Law and hope you make a mistake so that they can take further advantage of the situaiton...

Have you gotten anything from the Tenant in writing?  How can you prove that the Tenant returned possession of the property to you and/or legally abandoned the rental?  Verbal conversations do not provide any proof of what was discussed and/or agreed to by all parties.  It is better to get something from the Tenant in writing so that you can prove that the Tenant has legally returned possession of the property to you so that you may begin your attempts to "mitigate your damages" and find new Tenants.

Let us know what you find out...