It depends which pension scheme you're in!
If you're in the RMDCP, you'll have joined either RM or the pension sometime after 1st April 2008. If so, you do have a pot of cash which you can access anytime after age 55.
This will tell you what you can do with your money: https://www.moneyadviceservice.org.uk/e ... on-schemes
If you're in the RMSPS/RMPP, you'll have joined RM or the pension sometime before the above date. If so you won't have a pot of money but you will have guaranteed index linked benefits payable until your death, with spouses benefits thereafter.
However it is possible to transfer your RMPP(post 2012) benefits into a DC pension by getting a Cash Equivalent Transfer Value.
More details can be found simply by looking at the RMPP website: https://www.royalmailpensionplan.co.uk/ ... erring-out
You will need to get the transfer 'signed off' by an IFA if your CETV is worth more than £30,000, for which there will be a fee payable. Some receiving pension firms may require IFA approval even if it's lower than £30k.
It is not possible to transfer your pre 2012 RMSPS benefits in the same way: https://www.royalmailsps.co.uk/im-not-r ... y-benefits