If the beneficiary's bank, in a side letter confirms that a SLC (which is a financial credit enhancement instrument and is fully transferrable and assignable) is only for hypothecation. Can it be called / encashed

Would be grateful for a clarification on the same. Thanks

The benefiaciary's bank in a side letter states that a SLC (which is a purely financial credit enhancement instrument and is fully transferrable and callable against demand) would be held in safe custody and can only be hypothecated. Could such an SLC be encashed / called upon even if such undertaki...