Would you kindly clarify the usages of "Can have to/could have to" and "can have had to/could have had to".
[STRIKE]Thanks in advance..[/STRIKE] (unnecessary)
Please give us some examples of a sentence using each one and we will comment. It's very difficult for us to comment on usage of short phrases. It's always much better if you try to use them in a sentence and then we can see if you are using them correctly.
Note that you don't need to use such formality in the forum. There is no requirement for "Sir/Madam" or "Regards" and you certainly don't need to thank us in advance. If you like our answers, you can click the "Like" button in each post to show your appreciation.