How can I use the TIE constraint in a specific step by using the self contact on a single part?

[mtkashani]

In my problem, I have one part which is a rectangular plate, I want to deform it in ten steps to change to a pipe then fix two side edges to each other by tie constraint and then apply pressure to the top and bottom edges in a new step (step 11).
The problem is: the constraint condition will be active from initial time and keep active through step 1 and step 11. So, I want to ask if someone know how to define a tie in certain time let it be active only in step 11. (the self contact is used in step 10 ).

I appreciate if you reply and help.