A non-assumption clause prevents a borrower from transferring an existing mortgage to another person without obtaining approval from the lender. This is similar to a sublease clause in an apartment rental agreement, where a tenant cannot move out and hand over the financial responsibility to a new tenant without first having that tenant approved by the property manager. The non-assumption clause is described in the loan agreement, and buyers should read it carefully if they foresee a transfer occurring in the future. If a borrower is interested in transferring a mortgage to another borrower, he or she should contact the lender and discuss the circumstances. The proposed borrower will need to complete the lender's required paperwork. If there is a non-assumption clause in a contract, this does not necessarily mean a transfer cannot take place; it just means that the lender needs to approve it first.