IFRS-16 modification (Decrease in scope)

[Muzammil Korai]

Based on illustrative examples 17 and 18 of IFRS-16 that relate to lease modification, I am unable to grasp the following points:
1: In the first step of decrease in scope modification, when the Right-of-Use (ROU) asset undergoes a proportional decrease, is the lease liability also decreased proportionately, or is its new value derived based on lease modification? (In example 17, a proportional decrease was applied, whereas in example 18, a new value was derived based on the decrease in scope part of the lease modification.)
2: If a new value is indeed derived, which discount rate should be employed in the first step? (The original rate or the revised one?)

[ngadidala@gmail.com]

There are two types of Scope Decrease as I understand from the standard.
a) Scope Decrease due to Term Reduction- The payments which fell off due to term reduction will result in reduction of liability with the PV of lost payments @ existing Discount Rate
b) Scope Reduction from Units/Area reduction: The liability reduction in this case takes place from ROU reduction percentage.

In both the above Scope Reductions, there can be Liability Remeasurement @New Discount Rate as a follow up change. For example if I lose 6 months of payments and payments are increased for 1000 to 1200 for the remaining periods, then Liability Reduction with Gain/Loss and Liability Remeasurement both will have to calculated in a step by step method.