How can Beijing people's social security in other places be transformed into Beijing social security?

Social security transfer process in different places: the social security center where the account is returned will issue an acceptance letter, and if it is transferred from other provinces, the remittance information will be issued; Different institutions have different requirements. It may be that the social security agency of the original unit issued a letter agreeing to transfer out and stamped it in the social security center of the current unit.