Find your form. To search, type in a keyword and/or choose a category. To search for archived forms from a previous tax year, choose a year in the drop down menu.
So don't worry so much about how to use  had had  as a unit of grammar, they will come together naturally when you want to express the verb ' to have ' in the past perfect. Let's consider a different verb for a moment like  to want .
The tenses of come are come, came, have come, had come, so have came and had came can't be used. The usual combinations are as follows. Note that the have tense goes with the will tense; the had tense goes with the would tense. The students ... who have come into contact ...