48 CFR 570.404: 570.404 Superseding leases.

(a) Consider executing a superseding lease to replace an existing lease when the Government need numerous or detailed modifications to the space that would cause complications or substantially change the present lease or when market conditions warrant renegotiation of an existing lease.

(b) If the value of the superseding lease exceeds the simplified lease acquisition threshold, the justification and approval requirements in FAR 6.3 and 506.3 apply. If the cost does not exceed the simplified lease acquisition threshold, the contracting officer may use the simplified procedures in 570.2 and explain the absence of competition in the file.