What needs to be done in the event that a trade is amended by one...

A new confirmation should be generated by both parties but there is no need to restart the confirmation cycle.

The amending party should verbally inform the other party.

A new confirmation should be generated and the confirmation cycle should restart and continue until the trade is completely matched by both parties.

A new confirmation need not be generated but the confirmation cycle must restart and continue until the trade is completely matched by both parties.