Tenant requesting change in the lease

[Linda Thomas]

Hello,

The lease is in 2 sisters names. One of the sisters contacted me asking when she can remove her sister from the lease? I think it is best to ask some follow up questions such as is the sister moving out? is someone else moving in? how would you handle this and would you just remove the sister from the lease if the one that is staying can afford the rent alone? also would you request proof that the sister is no longer going to be living there such as some type of document like a change of address form? would you type up a new lease and charge them for the fees to type up and make the change? 

looking for advice and suggestions, as always thank you all for your help!