3 table update query

Thanks all - lots of examples, let me detail this to make it a little clearer.

db1.tblMembers (empNum, empLogon): this table contains a record for every user

db2.tblTemp (empNum, newLogon): this table contains a list of new logons as the logon format is changing

db2.tblBooking (empLogon): this is the booking table, I need to update the empLogon (varchar) to contain the newLogon from tblTemp where tblTemp.empNum equal to tblMembers.empNum.

E.G. Current values:

tblBooking:
smithj
smithj
hillp

tblTemp:
2132, john.smith
2133, peter.hill

tblMembers (in different db)
2132, smithj
2133, hillp

After the update the values will be:

tblBooking:
john.smith
john.smith
peter.hill

Thanks!