Generally apart from break clauses (usually midway through a lease) companies are liable for the full lease cost and can't give early notice for termination.

In accounting terms, leases according to IFRS 16 are recognized as a lease liability and a contra right of use asset for the full term of the lease.

I'm not 100% certain on the rationale of an impairment (as it could be construed as no longer useful) but if these companies aren't using these properties, auditors may force them to impair their leases, meaning large write offs and accounting losses.