declare @lf varchar(2)=char(13)+char(10); /* Windows linefeed */
--declare @lf varchar(1)=char(10); /* *nix linefeed */
select left(yourfield,len(yourfield)-case when yourfield like '%'+@lf then len(@lf) else 0 end)
from yourtable
;
Edit: forgot the hyphen, so here's another solution
declare @lf varchar(2)=char(13)+char(10); /* Windows linefeed */
--declare @lf varchar(1)=char(10); /* *nix linefeed */
select case when yourfield like '%'+@lf then left(yourfield,len(yourfield)-len(@lf))+'-' else yourfield end
from yourtable
;