First cousins (2) of mine ran business for 4 years, one coming out and bring in my sister as a partner? Pros and cons? ?

My friend's two cousins run a business. Now younger cousin is moving out of business and only sole owner is elder cousin. 

They asking if my friend's sister can step in? 

How will tax be calculated from person who is moving to Out? 

How will it impact on new owner? 

Bank guarantee is not a problem. Can do same one cosigner after putting something for bank to hold. 

How will be the process? 

?2020-01-07T16:48:23Z

Oh one huge business rule 101...
Never go into business with family, any family..

Eva2020-01-07T15:59:17Z

If you are in the US, once there is a 50% change in ownership, the partnership ceases to exist and a final tax return must be filed. The elder cousin and your sister would form a new partnership. It would need a new federal ID and bank accounts. This is a complicated matter and they should consult with their attorney and accountant.