FAMILY VISIT VISA SLIP VALIDITY FOR APPLYING

Hi,
everyone
My sisiter got her family visit visa slip which was issued by Mofa one month back and now she wants to apply for visa along application and other required document.
some one know that how long validity of visa slip which was issued by Mofa a month back?
should she apply for visa procedeeing right now by getting appointment and how long validity of visa slip since date of issue?
thanks to everone who pay attention to get answer for question.

should get stamp within 90 days after issued from mofa, then within 30 days should travel after stamping from saudi embassy

I have got the family visit visa stamped from Saudi embassy. Its validity is 30 days that means I have to travel to Saudi Arabia within 30 days but I can't do it for some domestic reason. I will able to travel 10 days after the expiration of the visa.So what are my options?
Can I cancel the current Family visit visa and reapply for the visa again.
Can I re-Apply without cancelling current visa.

Thanks