Can a Letter of Authority be amended through verbal agreement?

Can a previously signed Letter of Authority obtained by a broker, be amended a year later if the client agrees over to the amendments over the phone? p.s. the amendment is the date.

Alasdair Taylor's answer to Can a Letter of Authority be amended through verbal agreement? (2016044437)

I don't know the answer to this one I'm afraid: I'm not familiar with this type of letter of authority.

However, you do need to be careful amending dates, to ensure there is no risk of a fraud.

EDIT: on the fraud point, see this blog post from Mark Anderson yesterday:

https://ipdraughts.wordpress.com/2011/05/16/backdating-contracts-can-be-...