Replacing a Tenant on a Joint Lease

I’m currently on a joint lease with two other tenants. There are three bedrooms, and we each pay one third of the total rent to the landlord. Utilities and Wi-Fi are separate and paid by the tenants.

I’m considering moving out in September and finding someone to take over my spot while the other two tenants remain in the unit. I contacted my landlord asking if they would consent to assigning my portion of the lease, but I haven’t received a response.

Since the other tenants are staying, would this be considered a roommate/occupancy arrangement rather than an assignment or sublet? If it is not considered a sublet or assignment, am I allowed to negotiate whatever amount I want to charge the new occupant, or would the maximum I could charge be limited to the amount I currently pay toward rent (i.e. one third of the total rent) and utilities?