Hello, Leonard-Jones, and welcome to the Grammar Exchange!
"should" only adds some improbability to Type 1 conditionals. You can consider your sentence:
- If I should see him, I will call you.
to be equivalent to:
- If by any chance I see him, I will call you.
"should" also allows inversion in the condition:
- Should I see him, I will call you.
Note: We hope to see you here again. Please remember that all sentences should start with a capital letter. I know that in informal communications capitalization is sometimes omitted. However, this is a grammar forum, and we usually make a point of both questions and answers being properly written, as far as possible .