update a table by comparing strings

I had this question after viewing compare a value with a semicolon delimeted.

So based upon the above post this is what I would like to do

table 1 : userid
row 1      prs
row 2      ppp

table2
                   useridlist

row1         ccc;ddd;eee;PRS;rrr
row2         qqq;www;ttt


so i need a query that takes value for row 1 ('prs')  and compares it with useridlist of table 2 and since there is a match in row1 of table2 . since there is a match remove 'PRS' from table2 and update table two row with the following value :  ccc;ddd;eee;rrr

Thanks