How companies are handling lease modifications considered seperate contracts

Summary:

When a lease modification meets the requirements to have the "accounting treated as new contract" but it is not a separate contract from a legal perspective as it's not a standalone seperate contract but an amendment to the existing contract, how are you handling the accounting but still administering the lease as one contract.

Content (required):

I.e, how are you measuring the financial term of the additional space at the current discount rate effective in the system as required, without remeasuring exisitng rou asset and lease liablity financial terms if they were measured using a different rate.

Version (include the version you are using, if applicable):