I'm not sure if JMP understands SQL related to UPDATE queries, based on this statement failing with "Query failed: table t1 may not be modified in access or evaluation..." I'm not sure this is possible.
Query(
Table( dt1, "t1" ),
"UPDATE t1 SET age = 10"
);
You can, however, do this with Update:
dt1 << Update(
With( dt2 ),
Match Columns( :name = :name ),
Replace columns in main table(:age)
);
If you have a more complex sql statement, you could create a SELECT query first using SQL to create a new table, then use this update function to update your original table.