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.
I migrated all my data and most of my apps to Base. It hasn't been easy. Keep in mind that it's like trying to get a larger foot into a small shoe. There will be many things you will have to simplify and rethink. There are still many things missing from Base that frustrate me, e.g. simple cutting and pasting cells, rows or columns. But MS wasn't fixing the old bugs in newer versions of Access. Rather they were making it worse. At least LO Base has ongoing bug fixes and is improving.
Another thing is start with the simple stuff. If you start w/ the hard stuff you'll probably just get frustrated and quit. Figure out how to just move one table. Issues that you will need to work on are many: field types, e.g. check boxes (I use TINYINT (1)), timestamps (I use DATETIME defauting to CURRENT_TIMESTAMP), and Memo to TEXT. Again use HeidiSQL to help with this. Also I think I used http://www.bullzip.com/products/a2m/i... and then had to hand fix some of the fields.