Hello,
About the only thing you are going to be able to move is the data. For forms & reports nothing known here. If you just want a connection to the the Access tables (and possibly queries) from Base you can do this through the built-in connector or through a JDBC connector (depends upon OS & LO bitwise). See this post → mdb files not loading to base. Your question lacks information so a note here. From the connector website:
Supported Access formats: 2000, 2003, 2007, 2010.
Now if you are looking to transfer data from the Access files to another DB that question is not relative to LibreOffice.
However, here is one way. You can use SQL Workbench/J, a cross-platform SQL query tool. You can use the UCanAccess JDBC connector referred to in the first link and whatever JDBC connector is needed to to connect to the database you have chosen to use. Once you have the connectors installed & working, there is a tool built in to SQL Workbenck/J called 'Data Pumper…". This will allow you to move the data between various databases you have connections to.
Just tested moving tables from .mdb & .accdb files to a MySQL database. Have used this for other data transfers in past also as well as numerous other SQL activities. SQL Workbench/J & UCanAccess connector are cross platform.
If this answers your question please tick the (upper left area of answer). It helps others to know there was an accepted answer.