Dear all,

I would be grateful for any references to authorities on the following
hypothetical:

Suppose that in their contract, (the "Original Contract") the parties
agree that the contract can only be changed or varied (I'm interested
in either, if in fact there is a difference) in writing, signed by
specified persons.

In what circumstances could a further contract ("Contract 2") be made
either (i) orally or (ii) by parties other than those specified
(assuming that apart from the contractual stipulation in the Original
Contract the parties to the Contract 2 had authority) or both (i) and
(ii)?

On principle, it seems to me that Contract 2 could be valid only if:
1. It dealt with subject matter substantially different to that
considered in the Original Contract. Whether any overlap would be
permissible being a difficult question. or
2. Possibly if Contract 2 rescinded the Original Contract and then
created a wholly new arrangement. (I must say I find this an
unconvincing way of reading the hypothetical stipulation above but I
suppose it's arguable.)

There must be many contracts in which such clauses are present but I
can find no cases on this issue. It seems a matter of practical
importance, since if enforceable such a clause would significantly
limit the scope for arguing that collateral contracts had been entered
into etc.

Any comments welcome.

Kind regards

Ger