SQL Command Not Properly Ended

Hi i given my query here. in that joings betweens tables is correct, but i am getting the following error
ora-00933 sql command not properly ended
can we have exists function inside if condition??

select distinct loc.authorization from account acct, location loc, iom_order iom
where loc.location_id = acct.location_id and acct.account_id = iom.account_id and iom.iom_order_id =140

if(loc.authorization is null and exists(
select distinct line.INTRALATA_PIC_FREEZE ,line.INTERLATA_PIC_FREEZE
from line line, iom_order iom, activity act
where ((line.INTRALATA_PIC_FREEZE='F' or line.INTERLATA_PIC_FREEZE='F')and line.line_id = act.component_id and act.component = 23 and act.iom_order_id = 140)
union all
select distinct trunk.INTRALATA_PIC_FREEZE ,trunk.INTERLATA_PIC_FREEZE
from trunk trunk, activity act
where ( (trunk.INTRALATA_PIC_FREEZE='F' or trunk.INTERLATA_PIC_FREEZE='F')andtrunk.trunk_id = act.component_id and act.component = 25 and act.iom_order_id = 140)
select distinct rcf.INTRALATA_PIC_FREEZE ,rcf.INTERLATA_PIC_FREEZE
from remote_call_fwd rcf, activity act
where((rcf.INTRALATA_PIC_FREEZE='F' or rcf.INTERLATA_PIC_FREEZE='F')and rcf.remote_call_fwd_id = act.component_id and act.component = 24 and act.iom_order_id = 140)
select distinct tsg.INTRALATA_PIC_FREEZE ,tsg.INTERLATA_PIC_FREEZE
from nodal_tsg tsg, activity act
where ((tsg..INTRALATA_PIC_FREEZE='F' or tsg.INTERLATA_PIC_FREEZE='F')and tsg.nodal_tsg_id = act.component_id and act.component = 5 and act.iom_order_id = 140))) Then
select distinct loc.authorization from order2misc o2m, location loc, iom_order iom where loc.location_id =
o2m.serv_loc_id and iom.iom_order_id =140
else
select distinct loc.authorization from account acct, location loc, iom_order iom
where loc.location_id = acct.location_id and acct.account_id = iom.account_id and iom.iom_order_id =140
end if;