We can use 'should' in 'if clauses' when we believe that the possibility of something happening is small.• If you should happen to see him before I do, can you tell him that I want to speak to him urgently?• If there should be a problem, just give me a call and I'll sort it out.• If anyone should ask where I am, say I'm in a meeting.

اليكم منى كل احترام وتقدير شكرا

2. There are three uses of should and would.
Referring to the present or future,
should is often used as an alternative to shall in connection with requests for advice or instruction: 'What do you think I should do now?
Should I write him a letter, send him an e-mail, or should I try to phone him up?'
Should is often used to talk about obligation and duty as an alternative to 'ought to':
'If you are still infectious, you should stay at home.
You shouldn't be out and about, infecting everybody you meet.'
'You really should open a bank account.
You shouldn't keep so much money in the house.
' 'People with fierce dogs should keep them on a leash at all times.'
Should is used after if when a slight possibility is suggested.
'If you should see her at the anniversary concert, do give her my best regards.'
'If I should bump into Tony, do you want me to remind him that he still owes you one hundred pounds?'