The sound of one hand clapping

The sound of one hand clapping is the same as the sound of two hands clapping. In a strained personal relationship, for example, instead of waiting for the other person to make the first move toward reconciliation you could start the process in your own mind, either by purposely creating a better opinion of the other person, or by imagining the two of you getting along with all of your differences. Sorry, you can't control with your imagination what the other person thinks or does (it simply doesn't work), but you can use imagined persuasion just as you might in a face to face meeting. As in any form of persuasion, however, the more your persuasion is based on a benefit to the other person, the more successful it is likely to be.
In a strained global relationship, assuming our theory is valid (which means workable). We might be able to get together even in a smallish group and rethink our relationship with one or both countries involved. Theoretically, of course, it ought to take only one person to make a change. On the other hand, the change of one person's relationship to a country might only produce a very small change, so the more people the better. The thing to remember, in this context, is that you are trying to change how you think or feel about the country, not trying to change the country. It's a subtle but important difference, and it applies to people as well as countries.