I assume that you are asking the meaning of the underlined words.
As with Factual Conditions, should can be used in the IF-clause; it has a meaning similar to ‘happened to/chanced to’ suggesting that the speaker sees the possibility as more remote than a with a distancing [past] tense,
1. If you should see Paul, he would be happy to hear your news.
The distancing verb form in the main clause (here: would be) makes it clear that this is a hypothetical conditional, less likely, in the speaker’s mind, than the situation expressed as a predictive conditional:
1a. If you should see Paul, he will be happy to hear your news.
Were to [for all persons], with a meaning very similar to should is also used in hypothetical conditionals:
1b. If you were to see Paul, he would be happy to hear your news.
In even more formal English, when should and were to are used, IF is omitted, and subject and verb are inverted:
1c. Should you see Paul, he would be happy to hear your news.
2. Were it to be fine tomorrow, we could finish the painting.