Tenant Wants to Have Significant Other Move-in

[Michael Craig]

Happy Friday,

Two roommates occupy one of my apartments - this is their third year living there and they are both great tenants. One tenant would like to have their significant other move in while the other tenant would like to move out and be taken off the lease. 

The significant other qualifies for the apartment (screening process has just been completed). What is the most effective way of going about this? Do I scrap the existing lease and make a new one? Do I keep the existing lease and add an amendment?  Your thoughts are much appreciated!