Nowadays, when modern PLCs have a lot of memory, insisting on reusing a timer is a bit strange... But I can imagine that some individuals have a lot of time to spare and wish to devote it to challenges of this kind.

An explicit answer to your request is a finite-state machine. It will allow easily using the same timer in many states with different time presets.

Get some reading on the topic to understand the idea - the Wikipedia is not a bad place to start. Then look for some implementations targeted on PLCs.

Hello,

you can use also the LGF (library of general functions).

There you can use the "FB LGF_Frequency" as a signal generator.

regards
CaOd

I made a quick example what you could use.