I read the material that the latest give up date should be b4 July.
Thus I think the final call waiting will be after July.
P.s. I like the term of 'call waiting'
Last year.....my son got waitting call on mid August! I had send letters to KV every months, when I went to regis., I sew all my letters on my son's file, so I think the letters is very helpful to get a sit! Now his study in KV and very happy to go to school every day!