Before the deal can come into force and become a formal treaty, it must also be ratified by both countries.

However, no such swap actually took place in any formal treaty.

Ceasefires may be declared as part of a formal treaty, but they have also been called as part of an informal understanding between opposing forces.

Blackfish proposed that a formal treaty conference with all of the leaders be held on the next day.

It was essentially a formal treaty of alliance.