"To merge two Launchpad accounts, you must be logged in on Launchpad, and have access to the e-mail address registered under the duplicated account. Once you’ve finished, the e-mail address of the duplicated account will be assigned to you, along with everything else owned by the duplicated account."
I suggest this wording:
"To merge two Launchpad accounts, you must be logged in on Launchpad, and have access to the e-mail address registered under the duplicated account. Once you’ve finished, the e-mail address of the duplicated account will be assigned to you, along with everything else owned by the duplicated account."